Related Party Transactions - Schedule of Related Parties (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Related Party Transaction [Line Items]
Natural gas purchases (net of sales) from affiliates	$ 44	$ 65	$ 232
Services to/(from) affiliates	29	28	(4)
Interest expense to affiliates	193	239	167
Dividends to Parent	469	472	517
Equity contributions from Parent	600	300	605
Affiliate [Member]
Related Party Transaction [Line Items]
Accounts receivable	13	16
Taxes receivable	0	3
Accounts payable	16	10
Taxes payable	2	0
Related Party [Member]
Related Party Transaction [Line Items]
Interest income from affiliates	0	38	0
Interest expense to affiliates	$ 0	$ 11	$ 0