Consolidated Balance Sheets (Unaudited) (Parenthetical) (USD $) In Millions, except Share data, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Investments:
Amortized cost of fixed maturity securities available-for-sale	$ 332,542	$ 333,599
Fixed maturity securities relating to variable interest entities	355,069	350,187
Cost of equity securities available-for-sale	3,241	3,012
Actively traded securities	628	662
Fair value option and trading securities relating to variable interest entities	17,494	17,423
Mortgage loans:
Mortgage loans valuation allowances	326	322
Mortgage Loans on Real Estate	57,139	57,706
Policy loans	11,762	11,764
Real estate and real estate joint ventures relating to variable interest entities	9,930	10,712
Real estate held-for-sale	1	186
Other limited partnership interests relating to variable interest entities	7,819	7,401
Short-term investments	13,908	13,955
Other invested assets relating to variable interest entities	16,433	16,229
Cash and cash equivalents relating to variable interest entities	8,573	7,585
Accrued investment income relating to variable interest entities	4,446	4,255
Premiums, reinsurance and other receivables relating to variable interest entities	23,031	21,859
Deferred policy acquisition costs and value of business acquired relating to variable interest entities	26,352	26,706
Other assets relating to variable interest entities	8,387	8,369
Separate account assets	316,434	317,201
Liabilities
Future policy benefits relating to variable interest entities	189,970	187,942
Policyholder account balances	209,498	212,885
Other policy-related balances relating to variable interest entities	15,369	15,214
Long-term debt, at estimated fair value, relating to variable interest entities	16,793	18,653
Other liabilities relating to variable interest entities	24,178	23,168
Separate account liabilities	316,434	317,201
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	1,127,994,116	1,125,224,024
Common stock, shares outstanding	1,124,800,229	1,122,030,137
Treasury stock, shares	3,193,887	3,193,887
Residential Mortgage Loans - FVO [Member]
Mortgage loans:
Mortgage Loans on Real Estate	352	338
Variable interest entities [Member]
Investments:
Fixed maturity securities relating to variable interest entities	4,152	4,005
Fair value option and trading securities relating to variable interest entities	88	92
Mortgage loans:
Mortgage Loans on Real Estate	1,140	1,621
Policy loans	3	2
Real estate and real estate joint ventures relating to variable interest entities	9	1,141
Other limited partnership interests relating to variable interest entities	53	53
Short-term investments	6	8
Other invested assets relating to variable interest entities	71	78
Cash and cash equivalents relating to variable interest entities	45	70
Accrued investment income relating to variable interest entities	28	26
Premiums, reinsurance and other receivables relating to variable interest entities	27	22
Deferred policy acquisition costs and value of business acquired relating to variable interest entities	263	255
Other assets relating to variable interest entities	139	152
Separate account assets	1,099	1,033
Liabilities
Future policy benefits relating to variable interest entities	591	516
Policyholder account balances	63	56
Other policy-related balances relating to variable interest entities	125	123
Long-term debt, at estimated fair value, relating to variable interest entities	996	1,868
Other liabilities relating to variable interest entities	79	88
Separate account liabilities	$ 1,099	$ 1,033