CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Statement of Financial Position [Abstract]
Trading investments, cost	$ 33,985	$ 29,049
Available-for-sale investments, cost	2,440,204	2,535,568
Allowance for credit losses on loans and leases	$ 1,227,362	$ 1,165,335
Preferred stock, par or stated value (in dollars per share)	$ 0.20	$ 0.20
Preferred stock, shares authorized (in shares)	20,000,000	20,000,000
Preferred stock, shares outstanding (in shares)	2,500,000	2,500,000
Preferred stock, liquidation preference (in dollars per share)	$ 100	$ 100
Common stock, par value (in dollars per share)	$ 0.20	$ 0.20
Common stock, shares authorized (in shares)	1,125,000,000	1,125,000,000
Common stock, shares issued (in shares)	434,600,000	432,000,000.0
Accumulated other comprehensive income, tax	$ (12,601)	$ (5,707)
Common stock held in treasury (in shares)	163,500,000	153,100,000