Variable Interest Entities (Change in Level 3 Assets and Liabilities) (Details 2) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Summary of changes in Level 3 liabilities measured at fair value on a recurring basis [Roll Forward]
Transfers from Level 1 to Level 2, Assets		$ 0	$ 0	$ 0
Transfers from Level 2 to Level 1, Assets		0	0	0
Transfers from Level 1 to Level 2, Liabilities		0	0	0
Transfers from Level 2 to Level 1, Liabilities		0	0	0
Consolidated investment entities [Member]
Summary of changes in Level 3 liabilities measured at fair value on a recurring basis [Roll Forward]
Transfers from Level 1 to Level 2, Assets		0	0	0
Transfers from Level 2 to Level 1, Assets		0	0	0
Transfers from Level 1 to Level 2, Liabilities		0	0	0
Transfers from Level 2 to Level 1, Liabilities		0	0	0
Consolidated investment entities [Member] | Corporate Debt Securities [Member]
Summary of changes in Level 3 assets held by consolidated investment entities
Balance, at the beginning of the period		0
Sales		(2)
Transfers into Level 3		2
Balance, at the end of the period		0	0
Consolidated investment entities [Member] | Common stocks [Member]
Summary of changes in Level 3 assets held by consolidated investment entities
Balance, at the beginning of the period		5	3	7
Total gains (losses) included in net income	[1]	(1)	2	(1)
Purchases		3	1
Sales		(2)
Transfers into Level 3		7	3	7
Transfers out of Level 3		(8)	(2)	(10)
Balance, at the end of the period		4	5	3
Changes in unrealized gains (losses) included in income relating to assets held at end of period	[1]	(1)	1
Consolidated investment entities [Member] | Syndicated loans [Member]
Summary of changes in Level 3 assets held by consolidated investment entities
Balance, at the beginning of the period		254	529	484
Total gains (losses) included in net income	[1]		7	(24)
Purchases		146	145	303
Sales		(28)	(24)	(36)
Settlements		(70)	(69)	(161)
Transfers into Level 3		266	405	776
Transfers out of Level 3		(388)	(435)	(813)
Balance, at the end of the period		180	254	529
Changes in unrealized gains (losses) included in income relating to assets held at end of period	[1]	(1)	3	(19)
Consolidated investment entities [Member] | Other assets [Member]
Summary of changes in Level 3 assets held by consolidated investment entities
Balance, at the beginning of the period		0	2,065	1,935
Total gains (losses) included in net income	[2]		1	170
Total gains (losses) included in other comprehensive income (loss)				(154)
Purchases				638
Sales			(1)	(524)
Balance, at the end of the period			0	2,065
Changes in unrealized gains (losses) included in income relating to assets held at end of period	[2]			20
Consolidated investment entities [Member] | CLO Debt [Member]
Summary of changes in Level 3 liabilities measured at fair value on a recurring basis [Roll Forward]
Balance, at the beginning of the period		$ 0	(6,630)	(6,030)
Total gains (losses) included in net income	[1]			215
Issues				(1,267)
Settlements				452
Balance, at the end of the period			0	(6,630)
Changes in unrealized gains/ (losses) included in income relating to liabilities held at end of period	[1]			219
Consolidated investment entities [Member] | Adjustments for New Accounting Pronouncement [Member] | Common stocks [Member]
Summary of changes in Level 3 assets held by consolidated investment entities
Balance, at the beginning of the period	[3]		(2)
Balance, at the end of the period	[3]			(2)
Consolidated investment entities [Member] | Adjustments for New Accounting Pronouncement [Member] | Syndicated loans [Member]
Summary of changes in Level 3 assets held by consolidated investment entities
Balance, at the beginning of the period	[3]		(304)
Balance, at the end of the period	[3]			(304)
Consolidated investment entities [Member] | Adjustments for New Accounting Pronouncement [Member] | Other assets [Member]
Summary of changes in Level 3 assets held by consolidated investment entities
Balance, at the beginning of the period	[3]		(2,065)
Balance, at the end of the period	[3]			(2,065)
Consolidated investment entities [Member] | Adjustments for New Accounting Pronouncement [Member] | CLO Debt [Member]
Summary of changes in Level 3 liabilities measured at fair value on a recurring basis [Roll Forward]
Balance, at the beginning of the period	[3]		(6,630)
Balance, at the end of the period	[3]			(6,630)
Consolidated investment entities [Member] | Adjusted for change in accounting policies [Member] | Common stocks [Member]
Summary of changes in Level 3 assets held by consolidated investment entities
Balance, at the beginning of the period			1
Balance, at the end of the period				1
Consolidated investment entities [Member] | Adjusted for change in accounting policies [Member] | Syndicated loans [Member]
Summary of changes in Level 3 assets held by consolidated investment entities
Balance, at the beginning of the period			225
Balance, at the end of the period				225
Consolidated investment entities [Member] | Adjusted for change in accounting policies [Member] | Other assets [Member]
Summary of changes in Level 3 assets held by consolidated investment entities
Balance, at the beginning of the period			0
Balance, at the end of the period				0
Consolidated investment entities [Member] | Adjusted for change in accounting policies [Member] | CLO Debt [Member]
Summary of changes in Level 3 liabilities measured at fair value on a recurring basis [Roll Forward]
Balance, at the beginning of the period			$ 0
Balance, at the end of the period				$ 0

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

[2] Included in other revenues in the Consolidated Statements of Operations.

[3] The cumulative effect of change in accounting policies includes the adoption impact of ASU 2015-02 and ASU 2014-13 – Consolidation: Measuring the Financial Assets and the Financial Liabilities of a Consolidated Collateralized Financing Entity (“ASU 2014-13”).