Business Held for Sale and Discontinued Operations - Held for Sale Balance Sheets (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Investments:
Cash and cash equivalents	$ 498	$ 815	$ 696
Total assets held for sale	59,052	62,709
Liabilities [Abstract]
Liabilities held for sale	58,277	59,576
Held for sale | VIAC and DSL
Investments:
Fixed maturities, available-for-sale, at fair value	21,904	22,075
Fixed maturities, at fair value using the fair value option	615	647
Short-term investments	352	430
Mortgage loans on real estate, net of valuation allowance	4,212	3,722
Derivatives	1,514	976
Other investments	351	258
Securities pledged	861	748
Total investments	29,809	28,856
Cash and cash equivalents	498	815
Short-term investments under securities loan agreements, including collateral delivered	473	202
Deferred policy acquisition costs and Value of business acquired	805	890
Sales Inducements	196	206
Deferred income taxes	404	520
Other assets	396	286
Assets held in separate accounts	28,894	30,934
Write-down of businesses held for sale to fair value less cost to sell	(2,423)	0
Total assets held for sale	59,052	62,709
Liabilities [Abstract]
Future policy benefits and contract owner account balances	27,065	27,205
Payables under securities loan agreement, including collateral held	1,152	872
Derivatives	782	174
Notes payable	350	350
Other liabilities	34	41
Liabilities related to separate accounts	28,894	30,934
Liabilities held for sale	$ 58,277	$ 59,576