Transactions with Affiliates Textuals (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Related Parties Textuals [Abstract]
Card Member receivables and loans purchased without recourse from TRS	$ 299,000	$ 262,000	$ 225,000
Participation Interest And Card Member Receivables Sold To Affiliates	6,200	9,400	5,700
Discount Revenue Earned From Purchased Cardmember Receivables And Loans	1,017	760	471
Uncharged Servicing Fees to Affiliates	305	234	253
Restricted Cash with Affiliates	93	100	0
Long Term Debt with Affiliates	7,523	270	0
Related Party Transaction [Line Items]
Loans to affiliates and other	14,136	14,527	$ 10,659
Participation Interests In Card Member Receivables Purchased	6,700	4,100
Collateralized [Member] | RFC VIII [Member]
Related Party Transaction [Line Items]
Loans to affiliates and other	$ 7,200	$ 5,000