Commitments and Contingencies (Future Minimum Capital Lease Payments) (Details) (USD $)
In Millions, unless otherwise specified
Dec. 31, 2014
Capital Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]  
2015 $ 42
2016 32
2017 20
2018 11
2019 4
Thereafter 8
Total 117
Less amount representing interest (12) [1]
Capital lease obligations $ 105
Capital leases  
Capital Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]  
Weighted average interest rate 5.30%
[1] The weighted average interest rate on our capital lease obligations as of December 31, 2014 was approximately 5.3 percent.