Income Taxes- Breakout of Provision (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Current taxes:
U.S. federal	$ 0	$ (4)	$ 1
U.S. state	2	0	1
Foreign	3	2	14
Deferred taxes:
U.S. federal	350	53	(479)
U.S. state	25	13	(34)
Foreign	2	64	45
Total income tax provision (benefit)	382	128	(452)
State and Local Jurisdiction [Member]
Income Tax Provision [Line Items]
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount	0	(2)	0
Foreign [Member]
Income Tax Provision [Line Items]
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount	$ 1	$ 53	$ 47