Consolidated Balance Sheets (Unaudited) (Parenthetical) (USD $) In Millions, except Share data, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Assets
Amortized cost of fixed maturity securities available-for-sale	$ 332,909	$ 334,780
Fixed maturity securities relating to variable interest entities	366,275	365,425
Cost of equity securities available-for-sale	3,133	3,076
Actively traded securities	714	704
Fair value option and trading securities relating to variable interest entities	16,471	16,689
Mortgage loans valuation allowances	315	305
Mortgage Loans on Real Estate	62,409	60,118
Policy loans	11,606	11,618
Real estate and real estate joint ventures relating to variable interest entities	10,310	10,525
Real estate held-for-sale	56	172
Other limited partnership interests relating to variable interest entities	8,074	8,085
Short-term investments	14,130	8,621
Other invested assets relating to variable interest entities	23,763	21,283
Cash and cash equivalents relating to variable interest entities	8,127	10,808
Accrued investment income relating to variable interest entities	4,298	4,120
Premiums, reinsurance and other receivables relating to variable interest entities	24,190	22,244
Deferred policy acquisition costs and value of business acquired relating to variable interest entities	24,003	24,442
Other assets relating to variable interest entities	7,980	7,862
Separate account assets	324,724	316,994
Liabilities
Future policy benefits relating to variable interest entities	191,217	189,586
Policyholder account balances	206,591	209,294
Other policy-related balances relating to variable interest entities	14,586	14,422
Long-term debt, at estimated fair value, relating to variable interest entities	17,714	16,286
Other liabilities relating to variable interest entities	28,040	24,437
Separate account liabilities	324,724	316,994
MetLife, Inc.’s stockholders’ equity:
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	200,000,000	200,000,000
Preferred stock, shares issued	84,000,000	84,000,000
Preferred stock, shares outstanding	84,000,000	84,000,000
Preferred stock, aggregate liquidation preference	$ 2,100	$ 2,100
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	3,000,000,000	3,000,000,000
Common stock, shares issued	1,156,311,419	1,153,998,144
Common stock, shares outstanding	1,114,347,885	1,131,927,894
Treasury stock, shares	41,963,534	22,070,250
Residential mortgage loans — FVO
Assets
Mortgage Loans on Real Estate	329	308
Variable interest entities
Assets
Fixed maturity securities relating to variable interest entities	4,326	4,266
Fair value option and trading securities relating to variable interest entities	56	60
Mortgage Loans on Real Estate	272	280
Policy loans	3	3
Real estate and real estate joint ventures relating to variable interest entities	8	8
Other limited partnership interests relating to variable interest entities	34	34
Short-term investments	24	20
Other invested assets relating to variable interest entities	70	56
Cash and cash equivalents relating to variable interest entities	54	57
Accrued investment income relating to variable interest entities	26	21
Premiums, reinsurance and other receivables relating to variable interest entities	29	21
Deferred policy acquisition costs and value of business acquired relating to variable interest entities	246	235
Other assets relating to variable interest entities	136	134
Separate account assets	1,167	1,128
Liabilities
Future policy benefits relating to variable interest entities	636	579
Policyholder account balances	34	33
Other policy-related balances relating to variable interest entities	220	198
Long-term debt, at estimated fair value, relating to variable interest entities	143	151
Other liabilities relating to variable interest entities	100	80
Separate account liabilities	$ 1,167	$ 1,128