Equity (Details Textuals 4) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
American Life Insurance Company [Member]
Statutory Accounting Practices [Line Items]
Statutory capital and surplus	$ 3,044,000,000	$ 3,310,000,000
Prescribed accounting practice difference in statutory captial and surplus	413,000,000	597,000,000
Statutory net income (loss)	317,000,000	334,000,000	803,000,000
MetLife Reinsurance Company of Vermont [Member]
Statutory Accounting Practices [Line Items]
Prescribed accounting practice difference in statutory captial and surplus	5,100,000,000	4,500,000,000
MetLife's Domestic Captive Life Reinsurance Subsidiaries [Member]
Statutory Accounting Practices [Line Items]
Statutory capital and surplus	4,200,000,000	3,400,000,000
Statutory net income (loss)	(154,000,000)	(130,000,000)	(621,000,000)
Principal U.S. Insurance Subsidiaries, Excluding American Life [Member]
Statutory Accounting Practices [Line Items]
Combined RBC ratio of the principal U.S. insurance subsidiaries, excluding American Life	in excess of 400%	in excess of 400%
Certain Foreign Insurance Subsidiaries [Member]
Statutory Accounting Practices [Line Items]
Statutory capital and surplus	4,700,000,000
Statutory net income (loss)	679,000,000
Other Foreign Operations, Excluding Japan [Member]
Statutory Accounting Practices [Line Items]
Statutory capital and surplus required	2,300,000,000
Statutory capital and surplus	$ 7,800,000,000
Japan [Member]
Statutory Accounting Practices [Line Items]
Adjusted capital	in excess of four times the 200% solvency margin ratio	in excess of four times the 200% solvency margin ratio