Income Taxes - Additional information (Detail) - USD ($) $ in Millions	1 Months Ended	3 Months Ended	12 Months Ended
	Oct. 31, 2024	Dec. 31, 2022	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Income Taxes
Income tax expense at U.S. federal statutory rate			21.00%	21.00%	21.00%
Equity in net losses of unconsolidated entities			$ (4)	$ 60	$ 67
Compensation expense recognized, tax benefit			18	15	14
Increase (decrease) in provision for income taxes due to impairments			14	50
Renewable Natural Gas [Member]
Income Taxes
Tax credits and adjustments			137	8
Low income housing investments [Member]
Income Taxes
Investment proportional amortization tax impact			78
Equity in net losses of unconsolidated entities				66	65
Income tax benefit from low-income housing investments			$ 104	$ 108	$ 99
Investment Program, Proportional Amortization Method, Elected, Income Tax Credit and Other Income Tax Benefit, before Amortization, Statement of Income or Comprehensive Income [Extensible Enumeration]			Income Tax Expense (Benefit)	Income Tax Expense (Benefit)	Income Tax Expense (Benefit)
Investment Program Proportional Amortization Method Elected, Income Tax Credit and Other Income Tax Benefit Before Amortization, Statement of Cash Flows Extensible Enumeration, Not Disclosed Flag			true
Variable interest entities interest expense			$ 24	$ 15	$ 14
Consideration for investment	$ 426
Investment cash payment	33
Interest payable	77
Increase (decrease) investments in unconsolidated entities	$ 349
Tax Year 2017 [Member]
Income Taxes
Income tax deposit paid		$ 103