Loans and Allowance for Credit Losses, Loans by Credit Impairment Methodology (Details) - USD ($) $ in Millions	Jun. 30, 2015		Mar. 31, 2015	Dec. 31, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Dec. 31, 2008
Loans and Allowance for Credit Losses, by Credit Impairment Method [Abstract]
Allowance for Credit Losses, Collectively evaluated	$ 9,091			$ 9,188
Allowance for Credit Losses, Individually evaluated	3,516			3,970
Allowance for credit losses, PCI loans	7			11	$ 8
Total allowance for credit losses	12,614		$ 13,013	13,169	13,834	$ 14,414	$ 14,971
Financing Receivable, Collectively evaluated	841,983			813,823
Financing Receivable, Individually evaluated	24,921			25,408
Purchased Credit Impaired Loans	21,555			23,320
Loans	888,459	[1]		862,551
Commercial Portfolio Segment [Member]
Loans and Allowance for Credit Losses, by Credit Impairment Method [Abstract]
Allowance for Credit Losses, Collectively evaluated	5,523			5,482
Allowance for Credit Losses, Individually evaluated	749			884
Allowance for credit losses, PCI loans	7			11
Total allowance for credit losses	6,279		6,333	6,377	6,400	6,354	6,103
Financing Receivable, Collectively evaluated	433,247			409,560
Financing Receivable, Individually evaluated	3,902			3,759
Purchased Credit Impaired Loans	873			1,507				$ 18,700
Loans	438,022			414,826
Consumer Portfolio Segment [Member]
Loans and Allowance for Credit Losses, by Credit Impairment Method [Abstract]
Allowance for Credit Losses, Collectively evaluated	3,568			3,706
Allowance for Credit Losses, Individually evaluated	2,767			3,086
Allowance for credit losses, PCI loans	0			0
Total allowance for credit losses	6,335		$ 6,680	6,792	$ 7,434	$ 8,060	$ 8,868
Financing Receivable, Collectively evaluated	408,736			404,263
Financing Receivable, Individually evaluated	21,019			21,649
Purchased Credit Impaired Loans	20,682			21,813				$ 40,100
Loans	$ 450,437			$ 447,725

[1] Parenthetical amounts represent assets and liabilities for which we have elected the fair value option.