CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities
Net income	$ 546	$ 482	$ 392
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation, amortization and accretion	49	46	45
Loss (gain) from revision of ARO and disposition of fixed assets	2	(3)	0
Non-cash interest expense	1	1	0
Allowance oil reduction to net realizable value	1	5	0
Undistributed equity earnings	(6)	(6)	(6)
Changes in operating assets and liabilities
Accounts receivable	7	(7)	(7)
Allowance oil	0	(6)	(3)
Prepaid expenses and other assets	0	(4)	(7)
Accounts payable	2	(7)	8
Deferred revenue and other unearned income	(11)	(4)	6
Accrued liabilities	6	10	4
Net cash provided by operating activities	597	507	432
Cash flows from investing activities
Capital expenditures	(38)	(49)	(58)
Acquisitions from Parent	(90)	(482)	(420)
Third party acquisitions	0	0	(38)
Contributions to investment	(25)	(28)	(12)
Return of investment	66	48	18
April 2017 Divestiture	0	0	1
Net cash used in investing activities	(87)	(511)	(509)
Cash flows from financing activities
Net proceeds from equity offerings	0	973	278
Borrowings under credit facilities	600	1,820	1,693
Repayments of credit facilities	0	(1,573)	(533)
Contributions from general partner	0	20	6
Proceeds from April 2017 Divestiture	0	0	20
Capital distributions to general partner	(510)	(738)	(1,035)
Distributions to noncontrolling interests	(17)	(16)	(19)
Distributions to unitholders and general partner	(519)	(423)	(268)
Net distributions to Parent	0	0	(66)
Other contributions from Parent	19	12	18
Credit facility issuance costs	0	(1)	(2)
Repayment of finance leases	(1)	0	0
Net cash (used in) provided by financing activities	(428)	74	92
Net increase in cash and cash equivalents	82	70	15
Cash and cash equivalents at beginning of the period	208	138	123
Cash and cash equivalents at end of the period	290	208	138
Non-cash investing and financing transactions:
Change in asset retirement obligation	0	2	0
Change in accrued capital expenditures	(3)	2	0
Other non-cash contributions from Parent	0	2	0
Net assets not contributed to the Partnership	$ 0	$ 0	$ (5)