Income Taxes Income Taxes (Details) (USD $) In Millions, unless otherwise specified	1 Months Ended	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Provision for income taxes		$ 3	$ 2
Effective tax rates		1.80%	1.00%
Federal statutory income tax rate		35.00%	35.00%
Gain on Disposition of Asset Group	48	48
Impairment of Long-Lived Assets Held-for-use		25	10
Deferred tax benefit from intangible asset impairment		5	2
Tax benefit from the expiration of statutes of limitations		4	2
Net deferred tax liabilities	$ 18	$ 18		$ 24