Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2018

Table Text Block [Abstract]

Revenue Recognition Standard Impact [Text Block]

The impact to the 2017 fiscal quarters and years ended December 31, 2017 and 2016 were as follows:

		Increase (Decrease)
		Three months ended								Year Ended December
(Millions)			December 31, 2017		September 30, 2017		June 30, 2017		March 31, 2017		2017		2016
Revenues
	Discount revenue	$	981	$	930	$	928	$	868	$	3,707	$	3,699
	Other		(78)		(71)		(64)		(65)		(278)		(253)
Expenses
	Marketing and business development		617		591		593		549		2,350		2,420
	Card Member rewards	$	286	$	268	$	271	$	254	$	1,079	$	1,026