Condensed Financial Information (Parent Company) (Details Textuals 2) (Parent Company [Member], USD $) In Millions, unless otherwise specified									9 Months Ended		3 Months Ended			12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012 Investments in Majority-owned Subsidiaries [Member]	Sep. 30, 2012 Investments in Majority-owned Subsidiaries [Member] $750 Million Preferred Stock of Exeter [Member]	Dec. 31, 2012 Investments in Majority-owned Subsidiaries [Member] $1.25 Billion Preferred Stock of Exeter [Member]	Dec. 31, 2012 Senior Notes, Affiliated [Member]	Dec. 31, 2011 Senior Notes, Affiliated [Member]	Sep. 30, 2012 Senior Notes, Affiliated [Member] $750 Million Senior Note Issued to Metropolitan Life Insurance Company [Member]	Sep. 30, 2012 Senior Notes, Affiliated [Member] $750 Million Senior Note Issued to Metropolitan Life Insurance Company [Member] $250 Million Senior Note Metropolitan Life Insurance Company [Member]	Sep. 30, 2012 Senior Notes, Affiliated [Member] $750 Million Senior Note Issued to Metropolitan Life Insurance Company [Member] $500 Million Senior Note Metropolitan Life Insurance Company [Member]	Dec. 31, 2012 Senior Notes, Affiliated [Member] $250 Million Senior Note Issued to Metropolitan Life Insurance Company [Member]	Oct. 02, 2012 Senior Notes, Affiliated [Member] $250 Million Senior Note Issued to Metropolitan Life Insurance Company [Member]	Dec. 31, 2012 Senior Notes, Affiliated [Member] $1.25 Billion Senior Note Issued to Affiliates [Member]	Dec. 31, 2012 Senior Notes, Affiliated [Member] $1.25 Billion Senior Note Issued to Affiliates [Member] $250 Million Senior Note Affiliated [Member]	Dec. 31, 2012 Senior Notes, Affiliated [Member] $1.25 Billion Senior Note Issued to Affiliates [Member] $500 Million Senior Note Affiliated [Member]	Dec. 31, 2012 Senior Notes, Affiliated [Member] $1.25 Billion Senior Note Issued to Affiliates [Member] $500 Million Senior Note Affiliated [Member]	Dec. 31, 2012 Senior Notes, Affiliated [Member] $750 Million Senior Note issued to MetLife Reinsurance Company of Delaware [Member]
Condensed Financial Statements, Captions [Line Items]
Senior notes	$ 15,669	$ 15,666				$ 2,750	$ 0	$ 750		$ 500		$ 250	$ 1,250	$ 250	$ 500	$ 500	$ 750
Investment in subsidiaries	81,769	74,281	2,000	750	1,250
Maturities of Senior Debt									$ 250
Debt Instrument, Maturity Date										Jun. 30, 2014	Oct. 01, 2019			Sep. 30, 2016	Jul. 15, 2021	Dec. 16, 2021	Sep. 30, 2032
Debt Instrument, Interest Rate, Effective Percentage										6.44%		3.57%		7.44%	5.64%	5.86%	4.21%