Acquisitions and Divestitures Textual ( Details) - USD ($) $ in Millions	3 Months Ended			12 Months Ended
	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Dec. 31, 2016
Business Events Textuals [Abstract]
Gain on sale of HFS Portfolios				$ (1,218)
Other Expense [Member] | Goodwill Impairment Charges [Domain]
Business Events Textuals [Abstract]
Goodwill And Intangible Asset Impairment			$ 384
Other Expense [Member]
Business Events Textuals [Abstract]
Goodwill And Intangible Asset Impairment			219
Other Expense [Member] | Write-down of technology and other assets to fair value [Member]
Business Events Textuals [Abstract]
Goodwill And Intangible Asset Impairment			$ 165
Costco [Member] | Other Expense [Member]
Business Events Textuals [Abstract]
Gain on sale of HFS Portfolios	$ (1,091)
JetBlue [Member] | Other Expense [Member]
Business Events Textuals [Abstract]
Gain on sale of HFS Portfolios		$ (127)