Sales of Businesses - Narrative (Details) - USD ($) $ in Millions	3 Months Ended				9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Dec. 31, 2020	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of businesses					$ 3,547	$ 0
Realized gains (losses) on subsidiaries	$ 0			$ (30)	$ 4	$ (30)
Neon Capital Limited
Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of businesses			$ 6
Realized gains (losses) on subsidiaries		$ 4		$ (30)