v3.6.0.2
Segment Information (details)
$ in Millions
3 Months Ended 12 Months Ended
Dec. 31, 2016
USD ($)
Sep. 30, 2016
USD ($)
Jun. 30, 2016
USD ($)
Mar. 31, 2016
USD ($)
Dec. 31, 2015
USD ($)
Sep. 30, 2015
USD ($)
Jun. 30, 2015
USD ($)
Mar. 31, 2015
USD ($)
Dec. 31, 2016
USD ($)
item
Dec. 31, 2015
USD ($)
Dec. 31, 2014
USD ($)
Segment reporting information                      
Number of reportable business segments | item                 3    
Premiums                 $ 24,534 $ 23,874 $ 23,713
Net investment income                 2,302 2,379 2,787
Fee income                 458 460 450
Other revenues                 263 99 145
Income tax expense $ 359 $ 231 $ 223 $ 226 $ 343 $ 379 $ 264 $ 315 1,039 1,301 1,397
Operating income (loss)                 2,967 3,437 3,641
Net realized investment gains [1]                 68 3 79
Total revenues 7,193 6,961 6,785 6,686 6,678 6,798 6,710 6,629 27,625 26,815 27,174
Net realized investment gains, net of tax                 47 2 51
Net income $ 943 $ 716 $ 664 $ 691 $ 866 $ 928 $ 812 $ 833 3,014 3,439 3,692
Property casualty [Member]                      
Segment reporting information                      
Premiums                 24,534 23,874 23,713
Net investment income                 2,302 2,379 2,787
Domestic [Member]                      
Segment reporting information                      
Total revenues                 25,904 25,127 25,103
International [Member]                      
Segment reporting information                      
Total revenues                 1,721 1,688 2,071
Reportable Segments [Member]                      
Segment reporting information                      
Premiums                 24,534 23,874 23,713
Net investment income                 2,302 2,379 2,787
Fee income                 458 460 450
Other revenues                 252 93 145
Total operating revenues                 27,546 26,806 27,095
Amortization and depreciation                 4,804 4,696 4,738
Income tax expense                 1,157 1,443 1,512
Operating income (loss)                 3,211 3,692 3,898
Reportable Segments [Member] | Business and International Insurance [Member]                      
Segment reporting information                      
Premiums                 14,620 14,521 14,512
Net investment income                 1,763 1,824 2,156
Fee income                 442 445 438
Other revenues                 176 23 46
Total operating revenues                 17,001 16,813 17,152
Amortization and depreciation                 2,956 2,907 2,909
Income tax expense                 659 769 798
Operating income (loss)                 2,048 2,170 2,347
Reportable Segments [Member] | Business and International Insurance [Member] | Domestic [Member]                      
Segment reporting information                      
Premiums                 12,904 12,625 12,305
Reportable Segments [Member] | Business and International Insurance [Member] | Domestic [Member] | Workers' compensation [Member]                      
Segment reporting information                      
Premiums                 3,969 3,867 3,711
Reportable Segments [Member] | Business and International Insurance [Member] | Domestic [Member] | Automobile [Member]                      
Segment reporting information                      
Premiums                 2,010 1,922 1,900
Reportable Segments [Member] | Business and International Insurance [Member] | Domestic [Member] | Commercial property [Member]                      
Segment reporting information                      
Premiums                 1,769 1,766 1,747
Reportable Segments [Member] | Business and International Insurance [Member] | Domestic [Member] | General liability [Member]                      
Segment reporting information                      
Premiums                 1,977 1,898 1,834
Reportable Segments [Member] | Business and International Insurance [Member] | Domestic [Member] | Commercial multi-peril [Member]                      
Segment reporting information                      
Premiums                 3,148 3,133 3,071
Reportable Segments [Member] | Business and International Insurance [Member] | Domestic [Member] | Other [Member]                      
Segment reporting information                      
Premiums                 31 39 42
Reportable Segments [Member] | Business and International Insurance [Member] | International [Member]                      
Segment reporting information                      
Premiums                 1,716 1,896 2,207
Reportable Segments [Member] | Bond & Specialty Insurance [Member]                      
Segment reporting information                      
Premiums                 2,088 2,085 2,076
Net investment income                 210 223 252
Other revenues                 20 22 19
Total operating revenues                 2,318 2,330 2,347
Amortization and depreciation                 457 467 482
Income tax expense                 307 272 348
Operating income (loss)                 653 633 727
Reportable Segments [Member] | Bond & Specialty Insurance [Member] | General liability [Member]                      
Segment reporting information                      
Premiums                 946 955 963
Reportable Segments [Member] | Bond & Specialty Insurance [Member] | Fidelity and surety [Member]                      
Segment reporting information                      
Premiums                 962 954 936
Reportable Segments [Member] | Bond & Specialty Insurance [Member] | Other [Member]                      
Segment reporting information                      
Premiums                 180 176 177
Reportable Segments [Member] | Personal Insurance [Member]                      
Segment reporting information                      
Premiums                 7,826 7,268 7,125
Net investment income                 329 332 379
Fee income                 16 15 12
Other revenues                 56 48 80
Total operating revenues                 8,227 7,663 7,596
Amortization and depreciation                 1,391 1,322 1,347
Income tax expense                 191 402 366
Operating income (loss)                 510 889 824
Reportable Segments [Member] | Personal Insurance [Member] | Automobile [Member]                      
Segment reporting information                      
Premiums                 4,013 3,512 3,316
Reportable Segments [Member] | Personal Insurance [Member] | Homeowners and Other [Member]                      
Segment reporting information                      
Premiums                 3,813 3,756 3,809
Other [Member]                      
Segment reporting information                      
Other revenues                 11 6  
Operating income (loss)                 (244) (255) (257)
After-tax interest expense                 $ 236 $ 242 $ 240
[1] Total other-than-temporary impairment (OTTI) losses were $(40) million, $(54) million and $(22) million for the years ended December 31, 2016, 2015 and 2014, respectively. Of total OTTI, credit losses of $(29) million, $(52) million and $(26) million for the years ended December 31, 2016, 2015 and 2014, respectively, were recognized in net realized investment gains. In addition, unrealized gains (losses) from other changes in total OTTI of $(11) million, $(2) million and $4 million for the years ended December 31, 2016, 2015 and 2014, respectively, were recognized in other comprehensive income (loss) as part of changes in net unrealized gains on investment securities having credit losses recognized in the consolidated statement of income.