Consolidated Balance Sheets - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Investments:
Fixed maturity securities available-for-sale, at estimated fair value (amortized cost: $286,069 and $271,676, respectively)	$ 308,931	$ 289,563
Equity securities available-for-sale, at estimated fair value (cost: $2,140 and $2,464, respectively)	2,513	2,894
Fair value option securities, at estimated fair value ($6 and $8, respectively, relating to variable interest entities)	16,745	13,923
Mortgage loans (net of valuation allowances of $314 and $304, respectively; includes $520 and $566, respectively, under the fair value option)	68,731	65,167
Policy loans	9,669	9,511
Real estate and real estate joint ventures (includes $25 and $59, respectively, of real estate held-for-sale)	9,637	8,891
Other limited partnership interests (includes $0 and $14, respectively, relating to variable interest entities)	5,708	5,136
Short-term investments, principally at estimated fair value	4,870	6,523
Other invested assets (includes $125 and $31, respectively, relating to variable interest entities)	17,263	19,303
Total investments	444,067	420,911
Cash and cash equivalents, principally at estimated fair value (includes $12 and $1, respectively, relating to variable interest entities)	12,701	12,651
Accrued investment income	3,524	3,308
Premiums, reinsurance and other receivables (includes $3 and $2, respectively, relating to variable interest entities)	18,423	15,445
Deferred policy acquisition costs and value of business acquired	18,419	17,590
Current income tax recoverable	0	20
Goodwill	9,590	9,220
Assets of disposed subsidiary	0	216,983
Other assets (includes $2 and $3, respectively, relating to variable interest entities)	8,167	7,058
Separate account assets	205,001	195,578
Total assets	719,892	898,764
Liabilities
Future policy benefits	177,974	166,636
Policyholder account balances	182,518	172,486
Other policy-related balances	15,515	13,402
Policyholder dividends payable	682	696
Policyholder dividend obligation	2,121	1,931
Payables for collateral under securities loaned and other transactions	25,723	25,873
Short-term debt	477	242
Long-term debt (includes $6 and $12, respectively, at estimated fair value, relating to variable interest entities)	15,686	16,441
Collateral financing arrangement	1,121	1,274
Junior subordinated debt securities	3,144	3,169
Liabilities of disposed subsidiary	0	202,707
Taxes Payable, Current	311	0
Deferred income tax liability	6,767	6,892
Other liabilities (includes $3 and $0, respectively, relating to variable interest entities)	23,982	23,735
Separate Accounts, Liability	205,001	195,578
Total liabilities	661,022	831,062
Contingencies, Commitments and Guarantees (Note 20)
MetLife, Inc.’s stockholders’ equity:
Preferred stock, par value $0.01 per share; $2,100 aggregate liquidation preference	0	0
Common stock, par value $0.01 per share; 3,000,000,000 shares authorized; 1,168,710,101 and 1,164,029,985 shares issued, respectively; 1,043,588,396 and 1,095,519,005 shares outstanding, respectively	12	12
Additional paid-in capital	31,111	30,944
Retained earnings	26,527	34,683
Treasury stock, at cost; 125,121,705 and 68,510,980 shares, respectively	(6,401)	(3,474)
Accumulated other comprehensive income (loss)	7,427	5,366
Total MetLife, Inc.’s stockholders’ equity	58,676	67,531
Noncontrolling interests	194	171
Total equity	58,870	67,702
Total liabilities and equity	$ 719,892	$ 898,764