Loans and Related Allowance for Credit Losses, Loans by Delinquency Status, Commercial (Details) - USD ($) $ in Millions		Mar. 31, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	[1]	$ 1,009,843	$ 962,265
Nonaccrual loans		6,156
Total Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total		567,735	515,719
Nonaccrual loans		2,875	2,254
Commercial and industrial loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total		405,020	354,125
Nonaccrual loans		1,779	1,545
Commercial real estate mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total		122,767	121,824
Nonaccrual loans		944	573
Commercial real estate construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total		20,812	19,939
Nonaccrual loans		21	41
Commercial lease financing receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total		19,136	19,831
Nonaccrual loans		131	95
Current-29 days past due and still accruing [Member] | Total Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total		563,816	512,406
Current-29 days past due and still accruing [Member] | Commercial and industrial loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total		402,706	352,110
Current-29 days past due and still accruing [Member] | Commercial real estate mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total		121,621	120,967
Current-29 days past due and still accruing [Member] | Commercial real estate construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total		20,696	19,845
Current-29 days past due and still accruing [Member] | Commercial lease financing receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total		18,793	19,484
30-89 days past due and still accruing [Member] | Total Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total		991	981
30-89 days past due and still accruing [Member] | Commercial and industrial loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total		511	423
30-89 days past due and still accruing [Member] | Commercial real estate mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total		174	253
30-89 days past due and still accruing [Member] | Commercial real estate construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total		94	53
30-89 days past due and still accruing [Member] | Commercial lease financing receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total		212	252
90 days past due and still accruing [Member] | Total Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total		53	78
90 days past due and still accruing [Member] | Commercial and industrial loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total		24	47
90 days past due and still accruing [Member] | Commercial real estate mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total		28	31
90 days past due and still accruing [Member] | Commercial real estate construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total		1	0
90 days past due and still accruing [Member] | Commercial lease financing receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total		$ 0	$ 0

[1] (2) Parenthetical amounts represent assets and liabilities that we are required to carry at fair value or have elected the fair value option.