Consolidated Balance Sheet (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Available for sale, amortized cost	$ 37,948.5	$ 41,155.7
Held to maturity, fair value	23,315.4	17,797.4
Financing receivable, deferred commitment fee	$ 10.4	$ 9.8
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Common stock, par value (in dollars per share)	$ 1.6667	$ 1.6667
Common stock, shares authorized (in shares)	560,000,000	560,000,000
Common stock, shares outstanding (in shares)	207,761,875	208,289,178
Treasury stock, shares (in shares)	37,409,649	36,882,346
Series D Preferred Stock
Preferred stock, shares outstanding (in shares)	5,000	5,000
Series E Preferred Stock
Preferred stock, shares outstanding (in shares)	16,000	16,000