Loans and Card Member Receivables (Details 2)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
GCSG | Card Member Loans
Credit Quality Indicator for Loans and Receivables
30+ Days Past Due as a % of Total	1.00%	1.70%
GCSG | Card Member Loans | Net Write-Off Rate - Principal Only
Credit Quality Indicator for Loans and Receivables
Net Write-Off Rate	1.40%	2.60%
GCSG | Card Member Loans | Net Write-Off Rate Principal Interest, and Fees
Credit Quality Indicator for Loans and Receivables
Net Write-Off Rate	1.80%	3.20%
GCSG | Card Member Receivables
Credit Quality Indicator for Loans and Receivables
30+ Days Past Due as a % of Total	0.60%	1.70%
GCSG | Card Member Receivables | Net Write-Off Rate - Principal Only
Credit Quality Indicator for Loans and Receivables
Net Write-Off Rate	0.50%	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	0.60%	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	0.60%	1.40%
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	1.00%	1.90%
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	1.20%	2.20%
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%	2.00%
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	0.50%	2.20%
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	0.50%	2.50%
GCS | Global Corporate Payments
Credit Quality Indicator for Loans and Receivables
90+ Days Past Billing as a % of total	0.40%	1.10%
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	0.40%	1.00%