Equity (Details 9) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Metropolitan Life Insurance Company [Member]
Statutory Accounting Practices [Line Items]
Statutory net income (loss)	$ 1,320	$ 1,970	$ 2,066
Statutory capital and surplus	14,295	13,507
American Life Insurance Company [Member]
Statutory Accounting Practices [Line Items]
Statutory net income (loss)	317	334	803
Statutory capital and surplus	3,044	3,310
MetLife Insurance Company Of Connecticut [Member]
Statutory Accounting Practices [Line Items]
Statutory net income (loss)	848	46	668
Statutory capital and surplus	5,331	5,133
Metropolitan Property and Casualty Insurance Company [Member]
Statutory Accounting Practices [Line Items]
Statutory net income (loss)	235	41	273
Statutory capital and surplus	1,987	1,857
Metropolitan Tower Life Insurance Company [Member]
Statutory Accounting Practices [Line Items]
Statutory net income (loss)	61	63	151
Statutory capital and surplus	$ 781	$ 828