Card Member Receivables and Loans (Details 3)	6 Months Ended
	Jun. 30, 2018	Jun. 30, 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	1.30%	0.90%
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	0.75%	0.82%
Global Consumer Services Group [Member] | Card Member Loans [Member] | Net Write-Off Rate [Member]
Credit Quality Indicator for Receivables and Loans
Credit Quality Indicators	1.06%	1.28%
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	0.69%	0.85%
Global Small Business Services [Member] | Card Member Receivables [Member] | Net Write-Off Rate [Member]
Credit Quality Indicator for Receivables and Loans
Credit Quality Indicators	1.56%	1.03%
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	0.98%	1.10%
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	0.07%	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	0.81%	0.84%