v3.10.0.1
Retirement Plans - Schedule of Weighted-Average Asset Allocations for U.S Pension Plans and International Pension Plans (Details) - Pension Plans [Member] - USD ($)
$ in Millions
May 31, 2018
May 31, 2017
May 31, 2016
Defined Benefit Plan Disclosure [Line Items]      
Fair Value of Plan Assets $ 23,566 $ 26,312  
U.S. Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Fair Value of Plan Assets $ 22,057 $ 24,933 $ 23,017
Actual % 100.00% 100.00%  
International Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Fair Value of Plan Assets $ 1,509 $ 1,379 1,254
Portion of Fair Value of Plan Assets $ 1,320 $ 1,206  
Actual % 100.00% 100.00%  
Fair Value Inputs Level 1 [Member] | U.S. Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Fair Value of Plan Assets $ 4,258 $ 4,429  
Fair Value Inputs Level 1 [Member] | International Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Portion of Fair Value of Plan Assets 104 95  
Fair Value Inputs Level 2 [Member] | U.S. Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Fair Value of Plan Assets 10,164 12,955  
Fair Value Inputs Level 2 [Member] | International Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Portion of Fair Value of Plan Assets 418 398  
Fair Value Inputs Level 3 [Member] | U.S. Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Fair Value of Plan Assets 209 129 $ 48
Cash And Cash Equivalents [Member] | U.S. Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Fair Value of Plan Assets $ 714 $ 1,076  
Actual % 3.00% 4.00%  
Cash And Cash Equivalents [Member] | U.S. Plans [Member] | Minimum [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Target % [1] 0.00% 0.00%  
Cash And Cash Equivalents [Member] | U.S. Plans [Member] | Maximum [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Target % [1] 5.00% 5.00%  
Cash And Cash Equivalents [Member] | International Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Portion of Fair Value of Plan Assets $ 24 $ 48  
Actual % 2.00% 4.00%  
Cash And Cash Equivalents [Member] | Fair Value Inputs Level 1 [Member] | U.S. Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Fair Value of Plan Assets $ 19 $ 26  
Cash And Cash Equivalents [Member] | Fair Value Inputs Level 1 [Member] | International Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Portion of Fair Value of Plan Assets 2 2  
Cash And Cash Equivalents [Member] | Fair Value Inputs Level 2 [Member] | U.S. Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Fair Value of Plan Assets 695 1,050  
Cash And Cash Equivalents [Member] | Fair Value Inputs Level 2 [Member] | International Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Portion of Fair Value of Plan Assets 22 46  
U.S. Large Cap Equity [Member] | U.S. Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Fair Value of Plan Assets [2] $ 2,449 $ 2,415  
Actual % [2] 11.00% 10.00%  
U.S. Large Cap Equity [Member] | Fair Value Inputs Level 1 [Member] | U.S. Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Fair Value of Plan Assets [2] $ 840 $ 830  
International Equity Securities [Member] | U.S. Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Fair Value of Plan Assets [2] $ 3,506 $ 3,521  
Actual % [2] 16.00% 14.00%  
International Equity Securities [Member] | International Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Portion of Fair Value of Plan Assets [2] $ 146 $ 137  
Actual % [2] 11.00% 11.00%  
International Equity Securities [Member] | Fair Value Inputs Level 1 [Member] | U.S. Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Fair Value of Plan Assets [2] $ 2,681 $ 2,747  
International Equity Securities [Member] | Fair Value Inputs Level 2 [Member] | U.S. Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Fair Value of Plan Assets [2] 172 157  
International Equity Securities [Member] | Fair Value Inputs Level 2 [Member] | International Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Portion of Fair Value of Plan Assets [2] 70 72  
Global Equity Funds [Member] | U.S. Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Fair Value of Plan Assets [2] $ 1,772 $ 3,276  
Actual % [2] 8.00% 13.00%  
Global Equity Funds [Member] | International Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Portion of Fair Value of Plan Assets [2] $ 228 $ 202  
Actual % [2] 17.00% 17.00%  
U.S. SMID Cap Equity [Member] | U.S. Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Fair Value of Plan Assets $ 780 $ 987  
Actual % 4.00% 4.00%  
U.S. SMID Cap Equity [Member] | Fair Value Inputs Level 1 [Member] | U.S. Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Fair Value of Plan Assets $ 780 $ 987  
Corporate Fixed Income Securities [Member] | U.S. Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Fair Value of Plan Assets $ 5,834 $ 8,163  
Actual % 26.00% 33.00%  
Corporate Fixed Income Securities [Member] | International Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Portion of Fair Value of Plan Assets [2] $ 306 $ 270  
Actual % [2] 23.00% 22.00%  
Corporate Fixed Income Securities [Member] | Fair Value Inputs Level 2 [Member] | U.S. Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Fair Value of Plan Assets $ 5,834 $ 8,163  
Corporate Fixed Income Securities [Member] | Fair Value Inputs Level 2 [Member] | International Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Portion of Fair Value of Plan Assets [2] 68 49  
Government Fixed Income Securities [Member] | U.S. Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Fair Value of Plan Assets [2] $ 4,872 $ 4,674  
Actual % [2] 22.00% 19.00%  
Government Fixed Income Securities [Member] | International Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Portion of Fair Value of Plan Assets [2] $ 452 $ 405  
Actual % [2] 34.00% 34.00%  
Government Fixed Income Securities [Member] | Fair Value Inputs Level 1 [Member] | International Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Portion of Fair Value of Plan Assets [2] $ 108 $ 95  
Government Fixed Income Securities [Member] | Fair Value Inputs Level 2 [Member] | U.S. Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Fair Value of Plan Assets [2] 3,345 3,454  
Government Fixed Income Securities [Member] | Fair Value Inputs Level 2 [Member] | International Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Portion of Fair Value of Plan Assets [2] 256 230  
Mortgage Backed And Other Fixed Income Securities [Member] | U.S. Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Fair Value of Plan Assets [2] $ 626 $ 603  
Actual % [2] 3.00% 2.00%  
Mortgage Backed And Other Fixed Income Securities [Member] | International Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Portion of Fair Value of Plan Assets [2] $ 168 $ 145  
Actual % [2] 13.00% 12.00%  
Mortgage Backed And Other Fixed Income Securities [Member] | Fair Value Inputs Level 2 [Member] | U.S. Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Fair Value of Plan Assets [2] $ 125 $ 129  
Alternative investments [Member] | U.S. Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Fair Value of Plan Assets [2] $ 1,573 $ 377  
Actual % [2] 7.00% 2.00%  
Alternative investments [Member] | U.S. Plans [Member] | Minimum [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Target % [1],[2] 0.00% 0.00%  
Alternative investments [Member] | U.S. Plans [Member] | Maximum [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Target % [1],[2] 10.00% 5.00%  
Alternative investments [Member] | International Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Portion of Fair Value of Plan Assets $ 19 $ 17  
Actual % 2.00% 1.00%  
Alternative investments [Member] | Fair Value Inputs Level 2 [Member] | International Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Portion of Fair Value of Plan Assets $ 19 $ 17  
Alternative investments [Member] | Fair Value Inputs Level 3 [Member] | U.S. Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Fair Value of Plan Assets [2] 209 129  
Other [Member] | U.S. Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Fair Value of Plan Liabilities (69) $ (159)  
Actual %   (1.00%)  
Other [Member] | International Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Portion of Fair Value of Plan Liabilities $ (23) $ (18)  
Actual % (2.00%) (1.00%)  
Other [Member] | Fair Value Inputs Level 1 [Member] | U.S. Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Fair Value of Plan Liabilities $ (62) $ (161)  
Other [Member] | Fair Value Inputs Level 1 [Member] | International Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Portion of Fair Value of Plan Liabilities (6) (2)  
Other [Member] | Fair Value Inputs Level 2 [Member] | U.S. Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Fair Value of Plan Assets   2  
Fair Value of Plan Liabilities (7)    
Other [Member] | Fair Value Inputs Level 2 [Member] | International Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Portion of Fair Value of Plan Liabilities $ (17) $ (16)  
Total Equities [Member] | U.S. Plans [Member] | Minimum [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Target % [1] 30.00% 30.00%  
Total Equities [Member] | U.S. Plans [Member] | Maximum [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Target % [1] 50.00% 50.00%  
Total Fixed Income Securities [Member] | U.S. Plans [Member] | Minimum [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Target % [1] 50.00% 50.00%  
Total Fixed Income Securities [Member] | U.S. Plans [Member] | Maximum [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Target % [1] 70.00% 70.00%  
[1] Target ranges have not been provided for international plan assets as they are managed at an individual country level.
[2] Certain investments that are measured at fair value using the net asset value per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy but are included in the total.