Consolidated Balance Sheets (Parenthetical) - USD ($)		Dec. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Debt securities available for sale, amortized cost		$ 3,380,000,000	$ 3,275,000,000
Debt securities available for sale, allowance for credit losses		0
Debt securities held-to-maturity, fair value		2,973,000,000	3,305,000,000
Debt securities held to maturity, allowance for credit losses		40,000.00
Loans held for sale	[1]	144,000,000	41,000,000
Unearned income on loans		$ 77,000,000	$ 1,000,000
Preferred stock, par value (USD per Share)		$ 0.01	$ 0.01
Preferred stock, liquidation preference per share (USD per Share)		$ 1,000	$ 1,000
Preferred stock, shares authorized (in shares)		20,000,000	20,000,000
Preferred stock, shares issued (in shares)		110,877	110,877
Common stock, par value (USD per Share)		$ 0.01	$ 0.01
Common stock, shares authorized (in shares)		500,000,000	500,000,000
Common stock, shares issued (in shares)		328,057,368	327,242,364
Treasury stock, shares (in shares)		6,427,839	2,227,804

[1] Amount represents loans for which we have elected the fair value option. See Note 25.