Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2026	Dec. 31, 2025
Investment in marketable equity securities, at cost	$ 83	$ 83
Investment securities available for sale, at cost	33,663	31,952
Investment securities held to maturity, at fair value	$ 8,360	$ 8,491
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	20,000,000	20,000,000
Class A common stock
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, shares authorized (in shares)	32,000,000	32,000,000
Common stock, shares issued (in shares)	10,684,129	11,133,974
Common stock, shares outstanding (in shares)	10,684,129	11,133,974
Class B common stock
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, shares authorized (in shares)	2,000,000	2,000,000
Common stock, shares issued (in shares)	1,005,185	1,005,185
Common stock, shares outstanding (in shares)	1,005,185	1,005,185