Other Intangible Assets and Liabilities (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Finite-Lived Intangible Assets and Liabilities [Line Items]
Amortized intangible assets, gross carrying amount	$ 660		$ 660		$ 660
Amortized intangible assets, accumulated amortization	211		211		192
Amortized intangible liabilities, gross carrying amount	1,403		1,403		1,403
Amortized intangible liabilities, accumulated amortization	786		786		$ 736
Amortization of Intangible Assets	9	$ 8	19	$ 39
Amortization of Intangible Liabilities	25	$ 27	50	$ 61
Finite-Lived Intangible Assets and Liabilities, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Amortization of intangible assets, Remainder of 2016	20		20
Amortization of intangible liabilities, Remainder of 2016	51		51
Amortization of intangible assets, 2017	36		36
Amortization of intangible liabilities, 2017	96		96
Amortization of intangible assets, 2018	33		33
Amortization of intangible liabilities, 2018	90		90
Amortization of intangible assets, 2019	31		31
Amortization of intangible liabilities, 2019	27		27
Amortization of intangible assets, 2020	31		31
Amortization of intangible liabilities, 2020	$ 26		$ 26