Other Intangible Assets and Liabilities (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Finite-Lived Intangible Assets and Liabilities [Line Items]
Amortized intangible assets, gross carrying amount	$ 646		$ 2,031
Amortized intangible assets, accumulated amortization	165		1,519
Amortized intangible liabilities, gross carrying amount	1,403		2,056
Amortized intangible liabilities, accumulated amortization	655		1,274
Amortization of Intangible Assets	31	77
Amortization of Intangible Liabilities	34	44
Finite-Lived Intangible Assets and Liabilities, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Amortization of intangible assets, Remainder of 2015	25
Amortization of intangible liabilities, Remainder of 2015	81
Amortization of intangible assets, 2016	33
Amortization of intangible liabilities, 2016	101
Amortization of intangible assets, 2017	33
Amortization of intangible liabilities, 2017	96
Amortization of intangible assets, 2018	31
Amortization of intangible liabilities, 2018	90
Amortization of intangible assets, 2019	31
Amortization of intangible liabilities, 2019	$ 27