Settlement Assets and Obligations (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Settlement assets:
Cash and cash equivalents	$ 1,620,000,000	$ 1,426,000,000
Investment securities	0	1,000,000
Due from card associations, bank partners, and merchants	13,175,000,000	6,723,000,000
Total settlement assets	14,795,000,000	8,150,000,000
Settlement obligations:
Payment instruments outstanding	12,000,000	34,000,000
Card settlements due to merchants	14,783,000,000	8,116,000,000
Total settlement obligations	14,795,000,000	$ 8,150,000,000
Net changes in settlement assets and obligations	$ 0