Related Party Transactions - Transco and NWP (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Jan. 31, 2025	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Mar. 01, 2019
Related Party Transaction [Line Items]
Regulatory Liabilities		$ 1,385	$ 1,365
Employer's contributions charged to expense under defined contribution plan		69	60	$ 53
Accounts payable		$ 1,613	1,379
Related Party Transaction, Rate		4.00%
Revenues		$ 10,503	10,907	10,965
Transcontinental Gas Pipe Line Company, LLC [Member]
Related Party Transaction [Line Items]
Regulatory Liabilities		1,034	1,005
Employer's contributions charged to expense under defined contribution plan		13	12	11
Equity-based compensation expense		6	6	6
Interest Income, Other		58	87	36
Revenues		2,964	2,866	2,909
Credit To Expenses From Affiliates		6	14	10
Cash distributions to parent		1,145	1,220	838
Transcontinental Gas Pipe Line Company, LLC [Member] | Affiliated Entity
Related Party Transaction [Line Items]
Accounts and Financing Receivable, after Allowance for Credit Loss, Current		638	1,400
Interest Income, Other		51	81	31
Revenues		76	56	89
Related Party Transaction, Purchases from Related Party		5	7	18
Operating Expenses		344	324	345
Transcontinental Gas Pipe Line Company, LLC [Member] | Affiliated Entity | Subsequent Event [Member]
Related Party Transaction [Line Items]
Cash distributions to parent	$ 246
Transcontinental Gas Pipe Line Company, LLC [Member] | Pension Benefits [Member]
Related Party Transaction [Line Items]
Pension Cost (Reversal of Cost)		1	2	4
Regulatory Liability, Deferred For Future Rate Treatment		30	26
Regulatory Liability, Amortization Period					5 years
Transcontinental Gas Pipe Line Company, LLC [Member] | Other Postretirement Benefits [Member]
Related Party Transaction [Line Items]
Regulatory Liability, Amortization Period					5 years
Other Postretirement Benefits Cost (Reversal of Cost)		8	6	5
Regulatory Liabilities		31	31
Northwest Pipeline LLC [Member]
Related Party Transaction [Line Items]
Regulatory Liabilities		253	273
Employer's contributions charged to expense under defined contribution plan		3	3	3
Equity-based compensation expense		2	2	1
Interest Income, Other		2	1
Revenues		444	440	448
Operating Expenses		253	246	289
Cash distributions to parent		150	155	138
Northwest Pipeline LLC [Member] | Affiliated Entity
Related Party Transaction [Line Items]
Accounts and Financing Receivable, after Allowance for Credit Loss, Current			158
Accounts payable		26	0
Interest Income, Other		5	8	5
Operating Expenses		91	86	88
Northwest Pipeline LLC [Member] | Affiliated Entity | Subsequent Event [Member]
Related Party Transaction [Line Items]
Cash distributions to parent	24
Northwest Pipeline LLC [Member] | Pension Benefits [Member]
Related Party Transaction [Line Items]
Pension Cost (Reversal of Cost)		1	0	1
Northwest Pipeline LLC [Member] | Other Postretirement Benefits [Member]
Related Party Transaction [Line Items]
Other Postretirement Benefits Cost (Reversal of Cost)		1	0	$ 1
Regulatory Liabilities		$ 43	$ 42
Williams Companies Inc [Member] | Affiliated Entity | Subsequent Event [Member]
Related Party Transaction [Line Items]
Cash distributions to parent	$ 85