Fair Value 1 (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Financial assets for which carrying values equal or approximate fair value
Cash and cash equivalents	$ 33	$ 102	$ 196
Financial assets carried at other than fair value
Card Member loans, net	687	636
Loans to affiliates and other	10,345	14,136	14,527
Financial liabilities carried at other than fair value
Long-term debt	13,469	20,447
Long-term debt with affiliates	9,292	7,523	$ 270
Carrying Value [Member]
Financial assets for which carrying values equal or approximate fair value
Cash and cash equivalents	0	100
Other financial assets	26,300	24,900
Financial assets carried at other than fair value
Card Member loans, net	700	600
Loans to affiliates and other	10,300	14,100
Financial Liabilities:
Financial liabilities for which carrying values equal or approximate fair value	11,200	9,000
Financial liabilities carried at other than fair value
Long-term debt	13,500	20,400
Long-term debt with affiliates	9,300	7,500
Estimate of Fair Value Measurement [Member]
Financial assets for which carrying values equal or approximate fair value
Cash and cash equivalents	0	100
Other financial assets	26,300	24,900
Financial assets carried at other than fair value
Card Member loans, net	700	600
Loans to affiliates and other	10,400	14,100
Financial Liabilities:
Financial liabilities for which carrying values equal or approximate fair value	11,200	9,000
Financial liabilities carried at other than fair value
Long-term debt	13,700	20,500
Long-term debt with affiliates	9,400	7,300
Estimate of Fair Value Measurement [Member] | Level 1 [Member]
Financial assets for which carrying values equal or approximate fair value
Cash and cash equivalents	0	100
Other financial assets	100	100
Financial assets carried at other than fair value
Card Member loans, net	0	0
Loans to affiliates and other	0	0
Financial Liabilities:
Financial liabilities for which carrying values equal or approximate fair value	0	0
Financial liabilities carried at other than fair value
Long-term debt	0	0
Long-term debt with affiliates	0	0
Estimate of Fair Value Measurement [Member] | Level 2 [Member]
Financial assets for which carrying values equal or approximate fair value
Cash and cash equivalents	0	0
Other financial assets	26,200	24,800
Financial assets carried at other than fair value
Card Member loans, net	0	0
Loans to affiliates and other	2,800	7,400
Financial Liabilities:
Financial liabilities for which carrying values equal or approximate fair value	11,200	9,000
Financial liabilities carried at other than fair value
Long-term debt	13,700	20,500
Long-term debt with affiliates	9,400	7,300
Estimate of Fair Value Measurement [Member] | Level 3 [Member]
Financial assets for which carrying values equal or approximate fair value
Cash and cash equivalents	0	0
Other financial assets	0	0
Financial assets carried at other than fair value
Card Member loans, net	700	600
Loans to affiliates and other	7,600	6,700
Financial Liabilities:
Financial liabilities for which carrying values equal or approximate fair value	0	0
Financial liabilities carried at other than fair value
Long-term debt	0	0
Long-term debt with affiliates	$ 0	$ 0