Related Party Transactions - Transco and NWP (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended		6 Months Ended
	Jul. 31, 2025	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024	Dec. 31, 2024
Related Party Transaction [Line Items]
Accounts payable		$ 1,414		$ 1,414		$ 1,613
Related Party Transaction, Rate				4.00%
Revenues		2,781	$ 2,336	$ 5,829	$ 5,107
Transcontinental Gas Pipe Line Company, LLC [Member]
Related Party Transaction [Line Items]
Interest Income, Other		7	15	15	33
Revenues		791	710	1,561	1,442
Credit To Expenses From Affiliates		0	3	0	6
Cash distributions to parent				606	650
Transcontinental Gas Pipe Line Company, LLC [Member] | Affiliated Entity
Related Party Transaction [Line Items]
Interest Income, Other		6	14	12	30
Revenues		22	18	42	37
Related Party Transaction, Purchases from Related Party		3	1	5	3
Operating Expenses		82	75	174	160
Transcontinental Gas Pipe Line Company, LLC [Member] | Affiliated Entity | Subsequent Event [Member]
Related Party Transaction [Line Items]
Cash distributions to parent	$ 301
Northwest Pipeline LLC [Member]
Related Party Transaction [Line Items]
Interest Income, Other				2	1
Revenues		113	105	224	222
Cash distributions to parent				64	76
Northwest Pipeline LLC [Member] | Affiliated Entity
Related Party Transaction [Line Items]
Accounts payable		0		0		$ 26
Interest Income, Other		1	2	1	4
Operating Expenses		$ 21	$ 21	$ 45	$ 43
Northwest Pipeline LLC [Member] | Affiliated Entity | Subsequent Event [Member]
Related Party Transaction [Line Items]
Cash distributions to parent	42
Williams Companies Inc [Member] | Affiliated Entity | Subsequent Event [Member]
Related Party Transaction [Line Items]
Cash distributions to parent	$ 50