Fair Value (Financial Instruments Carried at Other Than Fair Value) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Assets
Policy loans	$ 9,670	$ 9,699
Liabilities
Collateral financing arrangement	1,048	1,060
Junior subordinated debt securities	3,148	3,147
Separate account liabilities	185,765	175,556
Carrying Value
Assets
Mortgage loans	78,325	75,453
Policy loans	9,670	9,699
Other invested assets	1,154	1,177
Premiums, reinsurance and other receivables	3,760	3,658
Other assets	314	326
Liabilities
Policyholder account balances	116,767	114,040
Long-term debt	12,836	12,820
Collateral financing arrangement	1,048	1,060
Junior subordinated debt securities	3,148	3,147
Other liabilities	3,287	2,963
Separate account liabilities	109,926	104,010
Estimated Fair Value
Assets
Mortgage loans	79,936	76,379
Policy loans	11,456	11,366
Other invested assets	1,154	1,176
Premiums, reinsurance and other receivables	3,919	3,797
Other assets	330	350
Liabilities
Policyholder account balances	118,800	114,924
Long-term debt	14,298	13,611
Collateral financing arrangement	851	853
Junior subordinated debt securities	3,958	3,738
Other liabilities	3,924	3,518
Separate account liabilities	109,926	104,010
Estimated Fair Value \| Level 1
Assets
Mortgage loans	0	0
Policy loans	0	0
Other invested assets	0	0
Premiums, reinsurance and other receivables	0	0
Other assets	0	0
Liabilities
Policyholder account balances	0	0
Long-term debt	0	0
Collateral financing arrangement	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	335	338
Other invested assets	793	793
Premiums, reinsurance and other receivables	1,018	903
Other assets	153	164
Liabilities
Policyholder account balances	0	0
Long-term debt	14,298	13,611
Collateral financing arrangement	0	0
Junior subordinated debt securities	3,958	3,738
Other liabilities	1,666	1,324
Separate account liabilities	109,926	104,010
Estimated Fair Value \| Level 3
Assets
Mortgage loans	79,936	76,379
Policy loans	11,121	11,028
Other invested assets	361	383
Premiums, reinsurance and other receivables	2,901	2,894
Other assets	177	186
Liabilities
Policyholder account balances	118,800	114,924
Long-term debt	0	0
Collateral financing arrangement	851	853
Junior subordinated debt securities	0	0
Other liabilities	2,258	2,194
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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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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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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