CONSOLIDATED STATEMENT OF PARTNERS' CAPITAL - USD ($) $ in Millions	Total	Accumulated Other Comprehensive Income (Loss)	Limited Partner [Member]
Balance at Dec. 31, 2016	$ 1,461	$ 5	$ 1,456
Other comprehensive income, net of tax	(8)	(8)	0
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, after Tax	(10)
Non-Cash Equity Contribution	8	0	8
Net income (loss)	(45)	0	(45)
Distribution to partners	(74)	0	(74)
Unit-based compensation expense	3	0	3
Balance at Dec. 31, 2017	1,345	(3)	1,348
Other comprehensive income, net of tax	(42)	(42)	0
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, after Tax	(42)
Non-Cash Equity Contribution	31	0	31
Net income (loss)	108	0	108
Distribution to partners	(95)	0	(95)
Panhandle Merger	(15)	2	(17)
Balance at Dec. 31, 2018	1,362	(47)	1,409
Other comprehensive income, net of tax	23		0
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, after Tax	23
Net income (loss)	589	0	589
Distribution to partners	(375)	0	(375)
Panhandle Merger	(3)	0	(3)
Balance at Dec. 31, 2019	$ 1,602	$ (24)	$ 1,626