Variable Interest Entities (Changes in Level 3 Assets and Liabilities) (Details 2) - Variable Interest Entity, Primary Beneficiary [Member] - Syndicated loans [Member] - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2020	Mar. 31, 2019
Summary of changes in Level 3 assets measured at fair value on a recurring basis [Rollforward]
Balance, at the beginning of the period		$ 143	$ 226
Total gains (losses) included in net income	[1]	(39)
Purchases		43	22
Sales		(7)	(1)
Settlements		(10)	(7)
Transfers into Level 3		248	25
Transfers out of Level 3		(76)	(148)
Balance, at the end of the period		302	$ 117
Changes in unrealized gains (losses) included in income relating to assets held at end of period	[1]	$ (37)

[1] Included in net investment income in the Consolidated Statements of Operations.