Consolidated Investment Entities - Consolidation of Investment Entities into the Consolidated Balance Sheets (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Variable Interest Entity, Consolidated, Carrying Amount, Assets [Abstract]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	$ 3,176	$ 4,056
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities [Abstract]
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	1,705	2,495
Assets:
Total investments and cash	67,305	65,879
Other assets	15,394	15,756
Assets held in consolidated investment entities	3,176	4,056
Assets held in separate accounts	77,605	66,185
Assets held for sale	59,052	62,709
Total assets	222,532	214,585
Liabilities and Shareholders' Equity:
Future policy benefits and contract owner account balances	65,805	64,848
Other liabilities	8,101	7,513
Liabilities held in consolidated investment entities	1,705	2,495
Liabilities related to separate accounts	77,605	66,185
Liabilities held for sale	58,277	59,576
Total liabilities	211,493	200,617
Equity attributable to common shareholders	10,009	12,995
Appropriated-consolidated investment entities	0	0
Noncontrolling interest	1,030	973
Total liabilities and shareholder's equity	222,532	214,585
Before Consolidation
Assets:
Total investments and cash	67,709	66,466
Other assets	15,431	15,757
Assets held in consolidated investment entities	0	0
Assets held in separate accounts	77,605	66,185
Assets held for sale	59,052	62,709
Total assets	219,797	211,117
Liabilities and Shareholders' Equity:
Future policy benefits and contract owner account balances	65,805	64,848
Other liabilities	8,101	7,513
Liabilities held in consolidated investment entities	0	0
Liabilities related to separate accounts	77,605	66,185
Liabilities held for sale	58,277	59,576
Total liabilities	209,788	198,122
Equity attributable to common shareholders	10,009	12,995
Noncontrolling interest	0	0
Total liabilities and shareholder's equity	219,797	211,117
CLOs
Assets:
Total investments and cash	0	0
Other assets	0	0
Assets held in consolidated investment entities	1,163	2,054
Assets held in separate accounts	0	0
Assets held for sale	0	0
Total assets	1,163	2,054
Liabilities and Shareholders' Equity:
Future policy benefits and contract owner account balances	0	0
Other liabilities	0	0
Liabilities held in consolidated investment entities	1,163	2,054
Liabilities related to separate accounts	0	0
Liabilities held for sale	0	0
Total liabilities	1,163	2,054
Equity attributable to common shareholders	0	0
Noncontrolling interest	0	0
Total liabilities and shareholder's equity	1,163	2,054
VOEs and LPs
Assets:
Total investments and cash	0	0
Other assets	0	0
Assets held in consolidated investment entities	2,013	2,002
Assets held in separate accounts	0	0
Assets held for sale	0	0
Total assets	2,013	2,002
Liabilities and Shareholders' Equity:
Future policy benefits and contract owner account balances	0	0
Other liabilities	0	0
Liabilities held in consolidated investment entities	587	459
Liabilities related to separate accounts	0	0
Liabilities held for sale	0	0
Total liabilities	587	459
Equity attributable to common shareholders	1,426	1,543
Noncontrolling interest	0	0
Total liabilities and shareholder's equity	2,013	2,002
CLOs Adjustments
Assets:
Total investments and cash	(8)	(17)
Other assets	(36)	0
Assets held in consolidated investment entities	0	0
Assets held in separate accounts	0	0
Assets held for sale	0	0
Total assets	(44)	(17)
Liabilities and Shareholders' Equity:
Future policy benefits and contract owner account balances	0	0
Other liabilities	0	0
Liabilities held in consolidated investment entities	(44)	(17)
Liabilities related to separate accounts	0	0
Liabilities held for sale	0	0
Total liabilities	(44)	(17)
Equity attributable to common shareholders	0	0
Noncontrolling interest	0	0
Total liabilities and shareholder's equity	(44)	(17)
VOEs Adjustments
Assets:
Total investments and cash	(396)	(570)
Other assets	(1)	(1)
Assets held in consolidated investment entities	0	0
Assets held in separate accounts	0	0
Assets held for sale	0	0
Total assets	(397)	(571)
Liabilities and Shareholders' Equity:
Future policy benefits and contract owner account balances	0	0
Other liabilities	0	0
Liabilities held in consolidated investment entities	(1)	(1)
Liabilities related to separate accounts	0	0
Liabilities held for sale	0	0
Total liabilities	(1)	(1)
Equity attributable to common shareholders	(1,426)	(1,543)
Noncontrolling interest	1,030	973
Total liabilities and shareholder's equity	(397)	(571)
Cash and cash equivalents
Assets:
Assets held in consolidated investment entities	217	133
Limited Partnerships/Corporations, at fair value
Assets:
Assets held in consolidated investment entities	1,795	1,936
Other assets
Assets:
Assets held in consolidated investment entities	75	34
VIEs
Variable Interest Entity, Consolidated, Carrying Amount, Assets [Abstract]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	3,094	3,856
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities [Abstract]
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	1,696	2,488
VIEs | Cash and cash equivalents
Variable Interest Entity, Consolidated, Carrying Amount, Assets [Abstract]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	216	133
VIEs | Corporate loans, at fair value using the fair value option
Variable Interest Entity, Consolidated, Carrying Amount, Assets [Abstract]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	1,089	1,921
VIEs | Limited Partnerships/Corporations, at fair value
Variable Interest Entity, Consolidated, Carrying Amount, Assets [Abstract]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	1,714	1,770
VIEs | Other assets
Variable Interest Entity, Consolidated, Carrying Amount, Assets [Abstract]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	75	32
VIEs | CLO notes, at fair value using the fair value option
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities [Abstract]
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	1,047	1,967
VIEs | Other liabilities
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities [Abstract]
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	649	521
VOEs
Variable Interest Entity, Consolidated, Carrying Amount, Assets [Abstract]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	82	200
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities [Abstract]
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	9	7
VOEs | Cash and cash equivalents
Variable Interest Entity, Consolidated, Carrying Amount, Assets [Abstract]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	1	0
VOEs | Corporate loans, at fair value using the fair value option
Variable Interest Entity, Consolidated, Carrying Amount, Assets [Abstract]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	0	32
VOEs | Limited Partnerships/Corporations, at fair value
Variable Interest Entity, Consolidated, Carrying Amount, Assets [Abstract]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	81	166
VOEs | Other assets
Variable Interest Entity, Consolidated, Carrying Amount, Assets [Abstract]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	0	2
VOEs | Other liabilities
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities [Abstract]
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	$ 9	$ 7