Consolidated Statements of Changes in Shareholders' Equity - Unaudited (Parenthetical) - $ / shares	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Fixed-to-Floating Rate Non-Cumulative Perpetual Preferred Stock, Series C, par value $1.00 per share
Preferred stock, dividends, per share, cash paid (usd per share)	$ 0.4375	$ 0.4375
Fixed-to-Floating Rate Non-Cumulative Perpetual Preferred Stock, Series D, par value $1.00 per share
Preferred stock, dividends, per share, cash paid (usd per share)	0.40625	0.40625
Fixed-to-Floating Rate Non-Cumulative Perpetual Preferred Stock, Series E, par value $1.00 per share
Preferred stock, dividends, per share, cash paid (usd per share)	0.403125	0.403125
Fixed-to-Floating Rate Non-Cumulative Perpetual Preferred Stock, Series F, par value $1.00 per share
Preferred stock, dividends, per share, cash paid (usd per share)	$ 0.375	$ 0.375