Variable Interest Entities (Changes in Level 3 Assets and Liabilities) (Details 2) - Consolidated investment entities [Member] - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Common stocks [Member]
Summary of changes in Level 3 assets measured at fair value on a recurring basis [Rollforward]
Balance, at the beginning of the period			$ 4
Total gains (losses) included in net income	[1]		4
Transfers into Level 3			4
Transfers out of Level 3			(1)
Balance, at the end of the period			11
Changes in unrealized gains (losses) included in income relating to assets held at end of period	[1]		4
Syndicated loans [Member]
Summary of changes in Level 3 assets measured at fair value on a recurring basis [Rollforward]
Balance, at the beginning of the period		$ 226	180
Total gains (losses) included in net income	[1]		2
Purchases		22	18
Sales		(1)	(1)
Settlements		(7)	(11)
Transfers into Level 3		25	61
Transfers out of Level 3		(148)	(49)
Balance, at the end of the period		$ 117	200
Changes in unrealized gains (losses) included in income relating to assets held at end of period	[1]		$ 2

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