Variable Interest Entities (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Variable Interest Entity [Line Items]
Accrued expenses and other liabilities	$ 2,331	$ 2,151	[1]
LIHTC Investments [Member]
Variable Interest Entity [Line Items]
Investment carrying value	189	104
Accrued expenses and other liabilities	$ 135	$ 84
LIHTC Investments [Member] | Minimum [Member]
Variable Interest Entity [Line Items]
Commitment, expected payment date	2017
LIHTC Investments [Member] | Maximum [Member]
Variable Interest Entity [Line Items]
Commitment, expected payment date	2020

[1] Adjusted for the retrospective adoption of ASU 2015-03. See New Accounting Standards in Note 2 for additional information.