Balance Sheet (Unaudited) - Transco - USD ($) $ in Millions	Jun. 30, 2025	Dec. 31, 2024
Assets, Current [Abstract]
Cash and cash equivalents	$ 903	$ 60
Inventory, Net	335	279
Other current assets and deferred charges	218	192
Current assets	3,221	2,661
Property, Plant and Equipment, Gross	59,391	57,395
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	(19,618)	(18,703)
Property, Plant and Equipment, Net	39,773	38,692
Other Assets, Noncurrent	1,838	1,830
Total assets	56,141	54,532
Liabilities, Current [Abstract]
Accounts payable	1,414	1,613
Other current liabilities	1,521	1,360
Total current liabilities	6,012	5,312
Contingent liabilities and commitments
Members' Equity [Abstract]
Retained Earnings (Accumulated Deficit)	(12,387)	(12,396)
Total liabilities and equity	56,141	54,532
Transcontinental Gas Pipe Line Company, LLC [Member]
Assets, Current [Abstract]
Cash and cash equivalents	0	0
Accounts and Other Receivables, Net, Current	10	12
Inventory, Net	84	81
Regulatory Assets, Current	124	74
Other current assets and deferred charges	27	24
Current assets	1,088	1,103
Property, Plant and Equipment, Gross	20,444	20,044
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	(6,256)	(5,941)
Property, Plant and Equipment, Net	14,188	14,103
Regulatory Assets, Noncurrent	265	320
Other Assets, Noncurrent	457	405
Total assets	15,998	15,931
Liabilities, Current [Abstract]
Accounts Payable, Trade, Current	230	258
Regulatory Liability, Current	81	58
Other current liabilities	295	181
Asset Retirement Obligation, Current	52	22
Long-Term Debt, Current Maturities	1,035	35
Total current liabilities	1,735	609
Long-Term Debt, Excluding Current Maturities	4,186	5,200
Regulatory Liabilities, Noncurrent	915	976
Asset Retirement Obligations, Noncurrent	569	593
Other Liabilities, Noncurrent	259	248
Contingent liabilities and commitments
Members' Equity [Abstract]
Members' Capital	5,088	5,088
Retained Earnings (Accumulated Deficit)	3,246	3,217
Total Members' Equity	8,334	8,305
Total liabilities and equity	15,998	15,931
Transcontinental Gas Pipe Line Company, LLC [Member] | Related Party
Assets, Current [Abstract]
Accounts and Financing Receivable, after Allowance for Credit Loss, Current	555	638
Accounts Receivable, after Allowance for Credit Loss, Current	7	24
Liabilities, Current [Abstract]
Accounts payable	42	55
Transcontinental Gas Pipe Line Company, LLC [Member] | Nonrelated Party
Assets, Current [Abstract]
Accounts Receivable, after Allowance for Credit Loss, Current	$ 281	$ 250