Loans and Card Member Receivables (Details 3)	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Global Consumer Services Group [Member] | Card Member Loans [Member] | Net Write-Off Rate - Principal Only [Member]
Credit Quality Indicator for Loans and Receivables
Credit Quality Indicators	2.70%	2.30%
Global Consumer Services Group [Member] | Card Member Loans [Member] | Net Write-Off Rate Principal Interest, and Fees [Member]
Credit Quality Indicator for Loans and Receivables
Credit Quality Indicators	3.20%	2.80%
Global Consumer Services Group [Member] | Card Member Loans [Member] | 30 Days Past Due as a % of Total [Member]
Credit Quality Indicator for Loans and Receivables
Credit Quality Indicators	1.20%	1.60%
Global Consumer Services Group [Member] | Card Member Receivables [Member] | Net Write-Off Rate - Principal Only [Member]
Credit Quality Indicator for Loans and Receivables
Credit Quality Indicators	2.00%	1.70%
Global Consumer Services Group [Member] | Card Member Receivables [Member] | Net Write-Off Rate Principal Interest, and Fees [Member]
Credit Quality Indicator for Loans and Receivables
Credit Quality Indicators	2.20%	1.80%
Global Consumer Services Group [Member] | Card Member Receivables [Member] | 30 Days Past Due as a % of Total [Member]
Credit Quality Indicator for Loans and Receivables
Credit Quality Indicators	0.80%	1.40%
Global Commercial Services [Member] | Global Small Business Services [Member] | Card Member Loans [Member] | Net Write-Off Rate - Principal Only [Member]
Credit Quality Indicator for Loans and Receivables
Credit Quality Indicators	2.10%	1.80%
Global Commercial Services [Member] | Global Small Business Services [Member] | Card Member Loans [Member] | Net Write-Off Rate Principal Interest, and Fees [Member]
Credit Quality Indicator for Loans and Receivables
Credit Quality Indicators	2.40%	2.10%
Global Commercial Services [Member] | Global Small Business Services [Member] | Card Member Loans [Member] | 30 Days Past Due as a % of Total [Member]
Credit Quality Indicator for Loans and Receivables
Credit Quality Indicators	1.10%	1.30%
Global Commercial Services [Member] | Global Small Business Services [Member] | Card Member Receivables [Member] | Net Write-Off Rate - Principal Only [Member]
Credit Quality Indicator for Loans and Receivables
Credit Quality Indicators	2.30%	1.90%
Global Commercial Services [Member] | Global Small Business Services [Member] | Card Member Receivables [Member] | Net Write-Off Rate Principal Interest, and Fees [Member]
Credit Quality Indicator for Loans and Receivables
Credit Quality Indicators	2.60%	2.10%
Global Commercial Services [Member] | Global Small Business Services [Member] | Card Member Receivables [Member] | 30 Days Past Due as a % of Total [Member]
Credit Quality Indicator for Loans and Receivables
Credit Quality Indicators	1.00%	1.70%
Global Corporate Payments [Member] | 90+ Days Past Billing As % Of Receivables [Member]
Credit Quality Indicator for Loans and Receivables
Credit Quality Indicators	0.60%	0.70%
Global Corporate Payments [Member] | Card Member Receivables [Member] | Net Write-Off Rate Principal Interest, and Fees [Member]
Credit Quality Indicator for Loans and Receivables
Credit Quality Indicators	2.20%
Global Corporate Payments [Member] | Card Member Receivables [Member] | Net Loss Ratio as a % of Charge Volume [Member]
Credit Quality Indicator for Loans and Receivables
Credit Quality Indicators		0.08%