Consolidated Balance Sheets (Unaudited) (Parenthetical) (USD $) In Millions, except Share data, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Assets
Amortized cost of fixed maturity securities available-for-sale	$ 341,198	$ 333,599
Fixed maturity securities relating to variable interest entities	368,070	350,187
Cost of equity securities available-for-sale	3,111	3,012
Actively traded securities	690	662
Fair value option and trading securities relating to variable interest entities	17,246	17,423
Mortgage loans valuation allowances	307	322
Mortgage Loans on Real Estate	58,038	57,706
Policy loans	11,756	11,764
Real estate and real estate joint ventures relating to variable interest entities	10,393	10,712
Real estate held-for-sale	173	186
Other limited partnership interests relating to variable interest entities	8,214	7,401
Short-term investments	12,240	13,955
Other invested assets relating to variable interest entities	17,905	16,229
Cash and cash equivalents relating to variable interest entities	8,783	7,585
Accrued investment income relating to variable interest entities	4,380	4,255
Premiums, reinsurance and other receivables relating to variable interest entities	23,814	21,859
Deferred policy acquisition costs and value of business acquired relating to variable interest entities	25,503	26,706
Other assets relating to variable interest entities	8,900	8,369
Separate account assets	319,480	317,201
Liabilities
Future policy benefits relating to variable interest entities	189,282	187,942
Policyholder account balances	215,226	212,885
Other policy-related balances relating to variable interest entities	15,026	15,214
Long-term debt, at estimated fair value, relating to variable interest entities	16,389	18,653
Other liabilities relating to variable interest entities	25,373	23,168
Separate account liabilities	319,480	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	1,130,449,364	1,125,224,024
Common stock, shares outstanding	1,119,087,159	1,122,030,137
Treasury stock, shares	11,362,205	3,193,887
Residential Mortgage Loans - FVO [Member]
Assets
Mortgage Loans on Real Estate	298	338
Variable interest entities [Member]
Assets
Fixed maturity securities relating to variable interest entities	4,097	4,005
Fair value option and trading securities relating to variable interest entities	67	92
Mortgage Loans on Real Estate	313	1,621
Policy loans	3	2
Real estate and real estate joint ventures relating to variable interest entities	8	1,141
Other limited partnership interests relating to variable interest entities	53	53
Short-term investments	35	8
Other invested assets relating to variable interest entities	56	78
Cash and cash equivalents relating to variable interest entities	61	70
Accrued investment income relating to variable interest entities	23	26
Premiums, reinsurance and other receivables relating to variable interest entities	33	22
Deferred policy acquisition costs and value of business acquired relating to variable interest entities	240	255
Other assets relating to variable interest entities	135	152
Separate account assets	1,140	1,033
Liabilities
Future policy benefits relating to variable interest entities	557	516
Policyholder account balances	63	56
Other policy-related balances relating to variable interest entities	197	123
Long-term debt, at estimated fair value, relating to variable interest entities	186	1,868
Other liabilities relating to variable interest entities	75	88
Separate account liabilities	$ 1,140	$ 1,033