Other Assets - Tax Equity Investments under the Proportional Amortization Method (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
Mar. 31, 2026	Dec. 31, 2025
Equity Method Investments
Total proportional amortization method investment	$ 1,903	$ 1,925
Unfunded equity contributions	$ 681	707
Funding period	5 years
Excluded tax equity investments	$ 44	45
Low-income housing
Equity Method Investments
Total proportional amortization method investment	1,877	1,897
Renewable energy and other
Equity Method Investments
Total proportional amortization method investment	$ 26	$ 28

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Amount of commitment and contingent commitment, including amount of delayed equity contribution, for investment that generates income tax credit and other income tax benefit under tax credit program elected to be accounted for using proportional amortization method. Includes, but is not limited to, commitment and contingent commitment related to investment under tax credit program not meeting condition for accounting under proportional amortization method.

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