Card Member Receivables and Card Member Loans 3 (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Global Consumer Services Group [Member] | Card Member Receivables [Member] | Net Write-Off Rate [Member]
Credit Quality Indicator for Receivables and Loans
Credit Quality Indicators	1.14%	1.01%
Global Consumer Services Group [Member] | Card Member Receivables [Member] | 30+ Days Past Due as a % of Total [Member]
Credit Quality Indicator for Receivables and Loans
Credit Quality Indicators	0.62%	0.89%
Global Consumer Services Group [Member] | Card Member Loans [Member] | Net Write-Off Rate [Member]
Credit Quality Indicator for Receivables and Loans
Credit Quality Indicators	1.03%	1.24%
Global Consumer Services Group [Member] | Card Member Loans [Member] | 30+ Days Past Due as a % of Total [Member]
Credit Quality Indicator for Receivables and Loans
Credit Quality Indicators	0.78%	0.71%
Global Small Business Services [Member] | Card Member Receivables [Member] | Net Write-Off Rate [Member]
Credit Quality Indicator for Receivables and Loans
Credit Quality Indicators	1.34%	1.11%
Global Small Business Services [Member] | Card Member Receivables [Member] | 30+ Days Past Due as a % of Total [Member]
Credit Quality Indicator for Receivables and Loans
Credit Quality Indicators	1.00%	1.06%
Global Corporate Payments [Member] | Card Member Receivables [Member] | Net Loss Ratio as a % of Charge Volume [Member]
Credit Quality Indicator for Receivables and Loans
Credit Quality Indicators	0.08%	0.08%
Global Corporate Payments [Member] | Card Member Receivables [Member] | 90+ days past billing as a percentage of receivables [Member]
Credit Quality Indicator for Receivables and Loans
Credit Quality Indicators	0.72%	0.83%