Loans and Interest Receivable - Consumer Receivables (Details) - Consumer Receivables - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan and interest receivable	$ 1,377	$ 1,322
Loan and interest receivables, allowance	187	57	$ 33	$ 30
Provision increase resulting from changes in macroeconomic conditions	90
Provision increase resulting from changes in portfolio expansion	$ 10
Threshold period, write-off of receivables	180 days
Threshold period, write-off of bankrupt accounts	90 days
Other Consumer Credit Products
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan and interest receivable	$ 94	92
Loan and interest receivables, allowance	$ 10	$ 9