Fair Value (Financial Instruments Carried at Other Than Fair Value) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Assets
Policy loans	$ 11,028	$ 11,258
Liabilities
Collateral financing arrangements	4,071	4,139
Junior subordinated debt securities	3,169	3,194
Separate account liabilities	308,620	301,598
Carrying Value
Assets
Mortgage loans	73,843	66,616
Policy loans	11,028	11,258
Real estate joint ventures	17	35
Other limited partnership interests	384	524
Other invested assets	506	537
Premiums, reinsurance and other receivables	5,140	2,822
Other assets	237	235
Liabilities
Policyholder account balances	124,475	125,040
Long-term debt	16,459	17,954
Collateral financing arrangements	4,071	4,139
Junior subordinated debt securities	3,169	3,194
Other liabilities	2,028	2,249
Separate account liabilities	119,498	112,119
Estimated Fair Value
Assets
Mortgage loans	75,129	68,539
Policy loans	13,015	13,351
Real estate joint ventures	69	104
Other limited partnership interests	413	615
Other invested assets	505	537
Premiums, reinsurance and other receivables	5,161	2,905
Other assets	269	267
Liabilities
Policyholder account balances	127,833	130,125
Long-term debt	18,016	19,360
Collateral financing arrangements	3,775	3,899
Junior subordinated debt securities	3,982	4,029
Other liabilities	2,028	2,250
Separate account liabilities	119,498	112,119
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	145	155
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	1,279
Real estate joint ventures	0	0
Other limited partnership interests	0	0
Other invested assets	0	2
Premiums, reinsurance and other receivables	1,982	484
Other assets	198	207
Liabilities
Policyholder account balances	0	0
Long-term debt	18,016	19,360
Collateral financing arrangements	0	0
Junior subordinated debt securities	3,982	4,029
Other liabilities	1,540	865
Separate account liabilities	119,498	112,119
Estimated Fair Value \| Level 3
Assets
Mortgage loans	75,129	68,539
Policy loans	11,900	12,072
Real estate joint ventures	69	104
Other limited partnership interests	413	615
Other invested assets	360	380
Premiums, reinsurance and other receivables	3,179	2,421
Other assets	71	60
Liabilities
Policyholder account balances	127,833	130,125
Long-term debt	0	0
Collateral financing arrangements	3,775	3,899
Junior subordinated debt securities	0	0
Other liabilities	488	1,385
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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