Parent Company Financial Statements - Statement of Cash Flows (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Operating Activities:
Net cash provided by operating activities	$ 11,898	$ (13,210)	$ 690
Investing Activities:
Net (decrease) increase in interest-bearing deposits with consolidated banking subsidiary	(12,998)	(25,292)	13,928
Purchases of available-for-sale securities	(50,245)	(44,301)	(23,089)
Net cash (used in) provided by investing activities	(12,991)	(39,483)	12,738
Financing Activities:
Proceeds from issuance of long-term debt, net of issuance costs	5,722	6,523	6,221
Payments for long-term debt	(4,143)	(2,046)	(2,545)
Proceeds from issuance of preferred stock, net of issuance costs	743	2,323	0
Payments for redemption of preferred stock	0	(1,500)	0
Repurchases of common stock	(1,200)	(1,319)	(3,781)
Repurchases of common stock for employee tax withholding	(106)	(83)	(95)
Payments for cash dividends	(1,120)	(1,033)	(970)
Net cash provided by (used in) financing activities	2,381	51,791	(13,351)
Net increase (decrease)	1,288	(902)	77
Cash and due from banks at beginning of period	3,145	4,047	3,970
Cash and due from banks at end of period	4,433	3,145	4,047
Parent Company
Operating Activities:
Net cash provided by operating activities	2,283	622	4,194
Investing Activities:
Net (decrease) increase in interest-bearing deposits with consolidated banking subsidiary	(189)	221	(199)
Proceeds from sales and maturities of available-for-sale securities	1,670	1,120	830
Purchases of available-for-sale securities	(1,701)	(1,204)	(836)
Investments in consolidated banking and non-banking subsidiaries	(11,102)	(9,330)	(10,784)
Sale or repayment of investment in consolidated banking and non-banking subsidiaries	9,100	7,875	7,920
Net cash (used in) provided by investing activities	(2,222)	(1,318)	(3,069)
Financing Activities:
Proceeds from issuance of long-term debt, net of issuance costs	5,722	4,281	6,221
Payments for long-term debt	(4,100)	(2,000)	(2,500)
Proceeds from issuance of preferred stock, net of issuance costs	743	2,350	0
Payments for redemption of preferred stock	0	(1,500)	0
Repurchases of common stock	(1,200)	(1,319)	(3,781)
Repurchases of common stock for employee tax withholding	(106)	(83)	(95)
Payments for cash dividends	(1,120)	(1,033)	(970)
Net cash provided by (used in) financing activities	(61)	696	(1,125)
Net increase (decrease)	0	0	0
Cash and due from banks at beginning of period	0	0	0
Cash and due from banks at end of period	$ 0	$ 0	$ 0