Preferred Shares - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025	Dec. 31, 2025
Preferred Shares [Line Items]
Preferred shares, authorized (in shares)	20,000,000		20,000,000		20,000,000
Preferred shares, par value (in dollars per share)	$ 1.667		$ 1.667		$ 1.667
Issuance of American Express preferred shares			$ 1,584	$ 0
Equity adjustments in connection with redemption of preferred shares	$ 16	$ 0	$ 16	$ 0
Liquidation price per share (in dollars per share)	$ 1,000,000		$ 1,000,000
Depositary shares, redemption amount (in dollars per share)	$ 1,000		$ 1,000
Series E Preferred Stock
Preferred Shares [Line Items]
Securities issued (in shares)	1,600
Fixed dividend rate per annum (as a percent)	6.45%		6.45%
Issuance of American Express preferred shares	$ 1,584
Series D Preferred Stock
Preferred Shares [Line Items]
Fixed dividend rate per annum (as a percent)	3.55%
Payments for redemption of preferred stock	$ 1,600