Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2025	Dec. 31, 2024
Held-to-maturity securities fair value	$ 7,164	$ 6,837
Financing receivable, unearned income	$ 292	$ 311
Common shares, par value (in usd per share)	$ 1	$ 1
Common shares, shares authorized (in shares)	2,100,000,000	2,100,000,000
Common shares, shares issued (in shares)	1,256,702,081	1,256,702,081
Treasury stock, shares (in shares)	143,749,779	149,915,630
Residential Mortgage
Loans held for sale	$ 62	$ 93