Fair Value (Financial Instruments Carried at Other Than Fair Value) (Details) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Assets
Policy loans	$ 11,115	$ 11,028
Liabilities
Collateral financing arrangements	4,059	4,071
Junior subordinated debt securities	3,169	3,169
Separate account liabilities	317,521	308,620
Carrying Value
Assets
Mortgage loans	75,773	73,843
Policy loans	11,115	11,028
Real estate joint ventures	8	17
Other limited partnership interests	350	384
Other invested assets	553	506
Premiums, reinsurance and other receivables	4,302	5,140
Other assets	277	237
Liabilities
Policyholder account balances	127,320	124,475
Long-term debt	16,472	16,459
Collateral financing arrangements	4,059	4,071
Junior subordinated debt securities	3,169	3,169
Other liabilities	3,171	2,028
Separate account liabilities	123,872	119,498
Estimated Fair Value
Assets
Mortgage loans	77,336	75,129
Policy loans	13,144	13,015
Real estate joint ventures	58	69
Other limited partnership interests	344	413
Other invested assets	553	505
Premiums, reinsurance and other receivables	4,406	5,161
Other assets	309	269
Liabilities
Policyholder account balances	130,441	127,833
Long-term debt	18,125	18,016
Collateral financing arrangements	3,775	3,775
Junior subordinated debt securities	4,041	3,982
Other liabilities	3,171	2,028
Separate account liabilities	123,872	119,498
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	168	145
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	1,115	1,115
Real estate joint ventures	0	0
Other limited partnership interests	0	0
Other invested assets	0	0
Premiums, reinsurance and other receivables	1,167	1,982
Other assets	196	198
Liabilities
Policyholder account balances	0	0
Long-term debt	18,125	18,016
Collateral financing arrangements	0	0
Junior subordinated debt securities	4,041	3,982
Other liabilities	2,641	1,540
Separate account liabilities	123,872	119,498
Estimated Fair Value \| Level 3
Assets
Mortgage loans	77,336	75,129
Policy loans	12,029	11,900
Real estate joint ventures	58	69
Other limited partnership interests	344	413
Other invested assets	385	360
Premiums, reinsurance and other receivables	3,239	3,179
Other assets	113	71
Liabilities
Policyholder account balances	130,441	127,833
Long-term debt	0	0
Collateral financing arrangements	3,775	3,775
Junior subordinated debt securities	0	0
Other liabilities	530	488
Separate account liabilities	$ 0	$ 0

Total amount of mortgage loans not valued on a recurring basis as of the balance sheet date.

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Fair value portion of other investments not otherwise specified in the taxonomy.

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The fair value portion of investments in other limited partnership interests.

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Fair value portion of the liability of policyholders for deposits held under the terms of insurance contracts.

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Including the current and noncurrent portions, carrying value as of the balance sheet date of long-term debt (with maturities initially due after one year or beyond the operating cycle if longer) identified as Junior Subordinated Notes, which have a lower priority than senior instruments.

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Amount before allowance of loans made to policy and contract holders using their life insurance contracts' cash value or separate accounts as collateral. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums over and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

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The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

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Fair value portion of other assets.

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Fair value portion of other liabilities.

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The book value of investments in real estate joint ventures including direct and indirect investments.

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Fair value portion of receivables, including, but not limited to, trade account receivables, note receivables, and loan receivables.

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Carrying value as of the balance sheet date, including the current and noncurrent portions, of collateralized debt obligations (with maturities initially due after one year or beyond the operating cycle, if longer). Such obligations include mortgage loans, chattel loans, and any other borrowings secured by assets of the borrower.

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Amount of liability for variable contracts that meet specified criteria that are backed by assets held in separate accounts and carried at the fair value of those assets.

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