Consolidated Statements of Comprehensive Income (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Statement of Comprehensive Income [Abstract]
Net income	$ 178us-gaap_NetIncomeLoss	$ 168us-gaap_NetIncomeLoss
Other comprehensive (loss) income:
Fair market value adjustment on cash flow hedges, net of income tax provision of $1 million		2
Reclassification adjustment for net realized losses on cash flow hedges included in interest expense, net of income tax provision of $1 million in each period	2	2
Foreign currency translation	(10)	2
Total other comprehensive (loss) income	(8)	6
Comprehensive income	$ 170us-gaap_ComprehensiveIncomeNetOfTax	$ 174us-gaap_ComprehensiveIncomeNetOfTax

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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