Related Parties - Investments in Unconsolidated Subsidiaries, Equity Securities and Other (Balance Sheet and Earnings Activity) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Schedule of Equity Method Investments [Line Items]
Net revenues	$ 873	$ 901	$ 2,422	$ 2,307
Expenses	11	14	38	41
Receivables	773		773		$ 523
Payables	19		19		20
Megapolis Group
Schedule of Equity Method Investments [Line Items]
Net revenues	583	622	1,609	1,537
Receivables	534		534		375
Other
Schedule of Equity Method Investments [Line Items]
Net revenues	290	279	813	770
Expenses	11	$ 14	38	$ 41
Receivables	239		239		148
Payables	$ 19		$ 19		$ 20