Loans and Card Member Receivables (Details 2) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Credit Quality Indicator for Loans and Receivables
90+ Days Past Billing as a % of total	0.30%	0.60%	0.30%	0.60%
Card Member Receivables
Credit Quality Indicator for Loans and Receivables
Net write-offs (recovery)	$ 32	$ 219	$ 89	$ 776
GCSG | Card Member Loans
Credit Quality Indicator for Loans and Receivables
30+ Days Past Due as a % of Total	0.70%	1.20%	0.70%	1.20%
GCSG | Card Member Loans | Net Write-Off Rate - Principal Only
Credit Quality Indicator for Loans and Receivables
Net Write-Off Rate			1.10%	2.70%
GCSG | Card Member Loans | Net Write-Off Rate Principal Interest, and Fees
Credit Quality Indicator for Loans and Receivables
Net Write-Off Rate			1.40%	3.20%
GCSG | Card Member Receivables
Credit Quality Indicator for Loans and Receivables
30+ Days Past Due as a % of Total	0.50%	0.80%	0.50%	0.80%
GCSG | Card Member Receivables | Net Write-Off Rate - Principal Only
Credit Quality Indicator for Loans and Receivables
Net Write-Off Rate			0.30%	2.00%
GCSG | Card Member Receivables | Net Write-Off Rate Principal Interest, and Fees
Credit Quality Indicator for Loans and Receivables
Net Write-Off Rate			0.40%	2.20%
GCS | Global Small Business Services | Card Member Loans
Credit Quality Indicator for Loans and Receivables
30+ Days Past Due as a % of Total	0.50%	1.10%	0.50%	1.10%
GCS | Global Small Business Services | Card Member Loans | Net Write-Off Rate - Principal Only
Credit Quality Indicator for Loans and Receivables
Net Write-Off Rate			0.70%	2.10%
GCS | Global Small Business Services | Card Member Loans | Net Write-Off Rate Principal Interest, and Fees
Credit Quality Indicator for Loans and Receivables
Net Write-Off Rate			0.80%	2.40%
GCS | Global Small Business Services | Card Member Receivables
Credit Quality Indicator for Loans and Receivables
30+ Days Past Due as a % of Total	0.60%	1.00%	0.60%	1.00%
GCS | Global Small Business Services | Card Member Receivables | Net Write-Off Rate - Principal Only
Credit Quality Indicator for Loans and Receivables
Net Write-Off Rate			0.30%	2.30%
GCS | Global Small Business Services | Card Member Receivables | Net Write-Off Rate Principal Interest, and Fees
Credit Quality Indicator for Loans and Receivables
Net Write-Off Rate			0.40%	2.60%
GCS | Global Corporate Payments | Card Member Receivables
Credit Quality Indicator for Loans and Receivables
Net write-offs (recovery)			$ (37)	$ 53
GCS | Global Corporate Payments | Card Member Receivables | Net Write-Off Rate Principal Interest, and Fees
Credit Quality Indicator for Loans and Receivables
Net Write-Off Rate			(0.10%)	2.20%