Accounting for Derivative Instruments and Hedging Activities Derivative instruments effect on the Company's condensed consolidated statements of operations (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Derivative instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative instruments, net	$ (5)	$ 5	$ (10)	$ (3)
Not Designated as Hedging Instrument [Member] | Gain (loss) on derivative instruments, net [Member] | Interest Rate Swap [Member] | Cash Flow Hedging [Member]
Derivative instruments, Gain (Loss) [Line Items]
Change in fair value of interest rate derivative instruments not designated as cash flow hedges	(3)	10	(3)	13
Loss reclassified from accumulated other comprehensive loss into earnings	(2)	(5)	(7)	(16)
Gain (loss) on derivative instruments, net	$ (5)	$ 5	$ (10)	$ (3)