Statement of Changes in Member's Equity - NWP - USD ($) $ in Millions	Total	Northwest Pipeline LLC [Member]	Member's Capital Northwest Pipeline LLC [Member]	Retained Earnings Northwest Pipeline LLC [Member]
Balance at beginning of year at Dec. 31, 2021			$ 1,074	$ 35
Net income	$ 2,049	$ 137		137
Cash distributions to parent		138		(138)
Balance at end of year at Dec. 31, 2022		1,108	1,074	34
Net income	3,179	180		180
Cash distributions to parent		155		(155)
Balance at end of year at Dec. 31, 2023		1,133	1,074	59
Net income	$ 2,225	180		180
Cash distributions to parent		150		(150)
Balance at end of year at Dec. 31, 2024		$ 1,163	$ 1,074	$ 89