Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 72	$ 69
Other comprehensive income:
Reclassification of cash flow hedge losses into earnings	0	1
Total other comprehensive income	0	1
Total comprehensive income	72	70
Total comprehensive income attributable to noncontrolling interests	0	0
Total comprehensive income attributable to partners	$ 72	$ 70