|
Income Taxes (Details 6) (USD $)
In Millions, unless otherwise specified |
Dec. 31, 2014
|
Dec. 31, 2013
|
Dec. 31, 2012
|
Dec. 31, 2011
|
|---|---|---|---|---|
| Unrecognized Tax Benefits That Would Impact Effective Tax Rate [Abstract] | ||||
| Unrecognized tax benefits that would reduce the effective tax rate | $ 33 | $ 34 | $ 41 | |
| Unrecognized tax benefits that would not reduce the effective tax rate | 118 | 25 | 74 | |
| Total unrecognized tax benefits | $ 151 | $ 59 | $ 115 | $ 107 |