Consolidated Balance Sheet (Unaudited) (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Investment securities, available for sale, amortized cost	$ 12,397	$ 10,691
Investment securities, held to maturity, fair value	13,865	14,308
Equity and other securities, cost	1,279	1,125
Loans and leases, unearned discount	$ 928	$ 868
Preferred stock, par value	$ 1	$ 1
Preferred stock, shares authorized	20,000,000	20,000,000
Preferred stock, shares issued	10,000,000	10,000,000
Preferred stock, liquidation preference per share	$ 25	$ 25
Common stock, par value	$ 0.50	$ 0.50
Common stock, shares authorized	250,000,000	250,000,000
Common stock, shares issued	179,436,779	179,436,779
Common stock issuable, shares	11,458	12,217
Treasury stock, common shares	12,724,121	13,300,298
Series A Series C Series And E Preferred Stock [Member]
Preferred stock, shares issued	350,000	350,000
Preferred stock, shares outstanding	350,000	350,000
Preferred stock, liquidation preference per share	$ 1,000	$ 1,000
Series F And Series G Preferred Stock [Member]
Preferred stock, shares issued	140,000	140,000
Preferred stock, shares outstanding	140,000	140,000
Preferred stock, liquidation preference per share	$ 10,000	$ 10,000