Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions		Sep. 30, 2017	Dec. 31, 2016
Loans held for sale	[1]	$ 1,341	$ 1,104
Held-to-maturity securities, fair value		10,109	10,007
Unearned income on loans		734	826
Loan securitization trust VIEs		2	3
Aggregate amount of certificates of deposit, denominations		$ 100,000	$ 100,000
Common shares, par value (in usd per share)		$ 1	$ 1
Common shares, shares authorized (in shares)		1,400,000,000	1,400,000,000
Common shares, shares issued (in shares)		1,256,702,081	1,256,702,081
Treasury stock, shares (in shares)		177,663,263	177,388,429
Residential Mortgage [Member]
Loans held for sale		$ 60	$ 62

[1] Total loans held for sale include real estate — residential mortgage loans held for sale at fair value of $60 million at September 30, 2017, and $62 million at December 31, 2016.