Consolidated Balance Sheets (Unaudited) (Parenthetical) (USD $) In Millions, except Share data, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Investments:
Amortized cost of fixed maturity securities available-for-sale	$ 339,287	$ 333,599
Fixed maturity securities relating to variable interest entities	367,056	350,187
Cost of equity securities available-for-sale	3,252	3,012
Actively traded securities	690	662
Fair value option and trading securities relating to variable interest entities	17,831	17,423
Mortgage loans:
Mortgage loans valuation allowances	294	322
Mortgage Loans on Real Estate	57,223	57,706
Policy loans	11,785	11,764
Real estate and real estate joint ventures relating to variable interest entities	10,101	10,712
Real estate held-for-sale	49	186
Other limited partnership interests relating to variable interest entities	7,964	7,401
Short-term investments	12,366	13,955
Other invested assets relating to variable interest entities	17,116	16,229
Cash and cash equivalents relating to variable interest entities	7,393	7,585
Accrued investment income relating to variable interest entities	4,234	4,255
Premiums, reinsurance and other receivables relating to variable interest entities	23,730	21,859
Deferred policy acquisition costs and value of business acquired relating to variable interest entities	25,915	26,706
Other assets relating to variable interest entities	9,136	8,369
Separate account assets	324,977	317,201
Liabilities
Future policy benefits relating to variable interest entities	189,675	187,942
Policyholder account balances	213,799	212,885
Other policy-related balances relating to variable interest entities	15,361	15,214
Long-term debt, at estimated fair value, relating to variable interest entities	16,783	18,653
Other liabilities relating to variable interest entities	25,214	23,168
Separate account liabilities	324,977	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	1,129,845,890	1,125,224,024
Common stock, shares outstanding	1,126,571,341	1,122,030,137
Treasury stock, shares	3,274,549	3,193,887
Residential Mortgage Loans - FVO [Member]
Mortgage loans:
Mortgage Loans on Real Estate	367	338
Variable interest entities [Member]
Investments:
Fixed maturity securities relating to variable interest entities	4,180	4,005
Fair value option and trading securities relating to variable interest entities	84	92
Mortgage loans:
Mortgage Loans on Real Estate	638	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	22	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	23	26
Premiums, reinsurance and other receivables relating to variable interest entities	21	22
Deferred policy acquisition costs and value of business acquired relating to variable interest entities	260	255
Other assets relating to variable interest entities	140	152
Separate account assets	1,164	1,033
Liabilities
Future policy benefits relating to variable interest entities	542	516
Policyholder account balances	63	56
Other policy-related balances relating to variable interest entities	203	123
Long-term debt, at estimated fair value, relating to variable interest entities	505	1,868
Other liabilities relating to variable interest entities	66	88
Separate account liabilities	$ 1,164	$ 1,033