Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Allowance for loans losses	$ 1,219	$ 1,271
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	1,125,000,000	1,125,000,000
Common stock, shares issued	461,000,000	459,000,000
Tax benefit for accumulated other comprehensive loss	$ 7	$ 45
Common stock held in treasury	312,000,000	305,000,000
Series A Junior Participate [Member]
Preferred stock, par value		$ 0.20
Preferred stock shares authorized		2,000,000
Preferred stock shares issued		0
Preferred stock shares outstanding		0
FFELP Loans [Member]
Allowance for loans losses	$ 255	$ 262
Private Education Loans [Member]
Allowance for loans losses	$ 964	$ 1,009