Consolidated Statements Of Comprehensive Income (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Statement of Comprehensive Income [Abstract]
Net income	$ 448	$ 322
Other comprehensive income (loss), net of tax:
Reclassification to earnings of gains and losses on derivative instruments accounted for as cash flow hedges	4	(1)
Change in value of derivative instruments accounted for as cash flow hedges	(4)	2
Change in value of available-for-sale securities	0	1
Actuarial loss relating to pension and other postretirement benefits	(1)	(1)
Foreign currency translation adjustment	(3)	(1)
Change in other comprehensive income from equity investments	(7)	7
Other comprehensive income (loss), net of tax	(11)	7
Comprehensive income	437	329
Less: Comprehensive income attributable to noncontrolling interest	272	238
Comprehensive income attributable to partners	$ 165	$ 91