Fair Value (Financial Instruments Carried at Other Than Fair Value) (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Assets
Policy loans	$ 11,549	$ 11,618
Liabilities
Collateral financing arrangements	4,152	4,196
Junior subordinated debt securities	3,194	3,193
Separate account liabilities	299,249	316,994
Estimated Fair Value
Assets
Mortgage loans	65,631	62,554
Policy loans	13,916	13,934
Real estate joint ventures	114	139
Other limited partnership interests	729	906
Other invested assets	541	562
Premiums, reinsurance and other receivables	5,680	3,157
Other assets	398	243
Liabilities
Policyholder account balances	129,880	139,359
Long-term debt	18,226	18,357
Collateral financing arrangements	3,925	3,961
Junior subordinated debt securities	4,036	4,173
Other liabilities	6,732	2,546
Separate account liabilities	111,427	116,665
Estimated Fair Value | Level 1
Assets
Mortgage loans	0	0
Policy loans	0	0
Real estate joint ventures	0	0
Other limited partnership interests	0	0
Other invested assets	162	172
Premiums, reinsurance and other receivables	0	0
Other assets	0	0
Liabilities
Policyholder account balances	0	0
Long-term debt	0	0
Collateral financing arrangements	0	0
Junior subordinated debt securities	0	0
Other liabilities	0	0
Separate account liabilities	0	0
Estimated Fair Value | Level 2
Assets
Mortgage loans	0	0
Policy loans	1,592	1,647
Real estate joint ventures	0	0
Other limited partnership interests	0	0
Other invested assets	2	70
Premiums, reinsurance and other receivables	3,264	713
Other assets	337	175
Liabilities
Policyholder account balances	0	0
Long-term debt	18,226	18,357
Collateral financing arrangements	0	0
Junior subordinated debt securities	4,036	4,173
Other liabilities	5,396	1,223
Separate account liabilities	111,427	116,665
Estimated Fair Value | Level 3
Assets
Mortgage loans	65,631	62,554
Policy loans	12,324	12,287
Real estate joint ventures	114	139
Other limited partnership interests	729	906
Other invested assets	377	320
Premiums, reinsurance and other receivables	2,416	2,444
Other assets	61	68
Liabilities
Policyholder account balances	129,880	139,359
Long-term debt	0	0
Collateral financing arrangements	3,925	3,961
Junior subordinated debt securities	0	0
Other liabilities	1,336	1,323
Separate account liabilities	0	0
Carrying Value
Assets
Mortgage loans	63,034	59,530
Policy loans	11,549	11,618
Real estate joint ventures	41	67
Other limited partnership interests	580	704
Other invested assets	541	562
Premiums, reinsurance and other receivables	5,578	3,070
Other assets	365	251
Liabilities
Policyholder account balances	124,476	134,219
Long-term debt	16,674	16,128
Collateral financing arrangements	4,152	4,196
Junior subordinated debt securities	3,194	3,193
Other liabilities	6,730	2,544
Separate account liabilities	$ 111,427	$ 116,665