CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 568	$ 556	$ 546
Other comprehensive gain (loss), net of tax:
Remeasurements of pension and other postretirement benefits related to equity method investments, net of tax	1	(1)	(2)
Comprehensive income	569	555	544
Noncontrolling interests	12	13	18
Comprehensive income attributable to the Partnership	$ 557	$ 542	$ 526