Loans and Card Member Receivables (Details 2) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Credit Quality Indicator for Loans and Receivables
90+ Days Past Billing as a % of total	0.30%	2.50%	0.30%	2.50%
Card Member Receivables
Credit Quality Indicator for Loans and Receivables
Net write-offs	$ (4)	$ (299)	$ (57)	$ (557)
GCSG | Card Member Loans
Credit Quality Indicator for Loans and Receivables
30+ Days Past Due as a % of Total	0.70%	1.60%	0.70%	1.60%
GCSG | Card Member Loans | Net Write-Off Rate - Principal Only
Credit Quality Indicator for Loans and Receivables
Net Write-Off Rate			1.30%	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			1.70%	3.30%
GCSG | Card Member Receivables
Credit Quality Indicator for Loans and Receivables
30+ Days Past Due as a % of Total	0.40%	1.30%	0.40%	1.30%
GCSG | Card Member Receivables | Net Write-Off Rate - Principal Only
Credit Quality Indicator for Loans and Receivables
Net Write-Off Rate			0.40%	2.20%
GCSG | Card Member Receivables | Net Write-Off Rate Principal Interest, and Fees
Credit Quality Indicator for Loans and Receivables
Net Write-Off Rate			0.50%	2.40%
GCS | Global Small Business Services | Card Member Loans
Credit Quality Indicator for Loans and Receivables
30+ Days Past Due as a % of Total	0.40%	1.60%	0.40%	1.60%
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			0.80%	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			1.00%	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	0.50%	2.10%	0.50%	2.10%
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%	2.40%
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			$ 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			(0.30%)	2.20%