Stockholders' Equity (Details) - USD ($) shares in Millions, $ in Millions |
1 Months Ended | 3 Months Ended | ||
---|---|---|---|---|
Apr. 27, 2017 |
Mar. 31, 2017 |
Mar. 31, 2016 |
Feb. 28, 2017 |
|
Class of Stock [Line Items] | ||||
Treasury Stock, Shares, Acquired | 1 | 2 | ||
Treasury Stock, Value, Acquired, Cost Method | $ 68 | $ 297 | ||
Subsequent Event [Member] | ||||
Class of Stock [Line Items] | ||||
Treasury Stock, Value, Acquired, Cost Method | $ 32 | |||
Common Stock [Member] | ||||
Class of Stock [Line Items] | ||||
Stock Repurchase Program, Authorized Amount | $ 1,000 | |||
Total remaining amount for repurchases under program | $ 932 | |||
Common Stock [Member] | Subsequent Event [Member] | ||||
Class of Stock [Line Items] | ||||
Total remaining amount for repurchases under program | $ 900 |