CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Trading investments, cost	$ 29,049	$ 12,551
Available-forsale investments at fair value, cost	2,535,568	1,986,957
Allowance for credit losses	$ 1,165,335	$ 1,361,723
Preferred stock, par value/stated value (in dollars per share)	$ 0.20	$ 0.20
Preferred stock, shares authorized (in shares)	20,000,000	20,000,000
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)	432,000,000.0	456,700,000
Accumulated other comprehensive income, tax	$ 5,707	$ (10,908)
Common stock held in treasury (in shares)	153,100,000	81,400,000
Series B Preferred Stock
Preferred stock, par value/stated value (in dollars per share)	$ 100	$ 100
Preferred stock, shares issued (in shares)	2,500,000	2,500,000