Certain Transfers of Financial Assets and Variable Interest Entities Tax Credit Variable Interest Entities (Details) - USD ($) $ in Millions		Jun. 30, 2019	Dec. 31, 2018
Other Assets		$ 10,936	$ 8,991
Community Development Investments [Member]
Other Assets	[1]	1,765	1,636
Community Development Investments [Member] | Limited Partner [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	[2]	2,496	2,207
Renewable Energy Program [Member]
Other Assets		53	86
Renewable Energy Program [Member] | Limited Partner [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	[2]	$ 96	$ 138

[1] At June 30, 2019 and December 31, 2018, the carrying value of community development investments excludes $70 million and $68 million of investments in funds that do not qualify for tax credits, respectively.

[2] At June 30, 2019 and December 31, 2018, the Company's maximum exposure to loss related to community development investments includes $697 million and $422 million of loans and $572 million and $639 million of unfunded equity commitments, respectively. At June 30, 2019 and December 31, 2018, the Company's maximum exposure to loss related to renewable energy partnerships includes $43 million and $52 million of unfunded equity commitments, respectively.