Consolidated Statements Of Comprehensive Income - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 336	$ 221
Other comprehensive income (loss), net of tax:
Change in value of derivative instruments accounted for as cash flow hedges	0	1
Change in value of available-for-sale securities	2	1
Actuarial gain (loss) relating to pension and other postretirement benefit plans	(9)	45
Foreign currency translation adjustments	(1)	(2)
Change in other comprehensive income from unconsolidated affiliates	(6)	(2)
Other comprehensive income (loss), net of tax	(14)	43
Comprehensive income	322	264
Less: Comprehensive income (loss) attributable to noncontrolling interest	10	(20)
Comprehensive income attributable to partners	$ 312	$ 284