Acquisitions and Dispositions (Details Textuals)	3 Months Ended			9 Months Ended		12 Months Ended			12 Months Ended			9 Months Ended		3 Months Ended		9 Months Ended
	Sep. 30, 2011 USD ($)	Mar. 31, 2011 USD ($)	Sep. 30, 2010 USD ($)	Sep. 30, 2011 USD ($)	Sep. 30, 2010 USD ($)	Dec. 31, 2010 USD ($)	Sep. 30, 2011 GBP (£)	Nov. 01, 2010 USD ($)	Dec. 31, 2010 American Life Insurance Company ("American Life") and Delaware American Life Insurance ("DelAm") Member Convertible Preferred Stock	Sep. 30, 2011 Japan [Member] USD ($)	Sep. 30, 2011 International Other Regions [Member] USD ($)	Sep. 30, 2011 Mitsui Sumitomo MetLife Insurance Co., LTD. ("MSI MetLife") [Member] JPY (¥)	Sep. 30, 2011 Mitsui Sumitomo MetLife Insurance Co., LTD. ("MSI MetLife") [Member] USD ($)	Sep. 30, 2011 MetLife Taiwan Insurance Company Limited [Member] USD ($)	Sep. 30, 2010 MetLife Taiwan Insurance Company Limited [Member] USD ($)	Sep. 30, 2011 MetLife Taiwan Insurance Company Limited [Member] USD ($)	Sep. 30, 2010 MetLife Taiwan Insurance Company Limited [Member] USD ($)
Business Acquisition [Line Items]
Equity Units, Shares Transferred									6,857,000
Minimum per unit fair value of fund assets backing certain U.K. unit-linked contracts							1
Goodwill
Goodwill								$ 6,959,000,000		$ 5,200,000,000	$ 1,800,000,000
Description of Transaction
Total purchase price for acquisition								16,390,000,000
Business Acquisition Reason						The Acquisition significantly broadened the Company’s diversification by product, distribution and geography, meaningfully accelerated MetLife’s global growth strategy, and provides the opportunity to build an international franchise leveraging the key strengths of ALICO.
Common stock, shares issued		68,570,000
Proceeds from issuance of common stock		2,966,000,000
Contingent Consideration
Change in value between the guaranteed amount and the fair value of the fund in relation to UK unit linked contracts specified in Stock Purchase Agreement that triggers a payment between American International Group, Incorporated to American Life Insurance Company and Delaware American Life Insurance Company							106,000,000
Contingent consideration	121,000,000			121,000,000				88,000,000
Costs Related to Acquisition
Business acquisition, cost of acquired entity transaction costs	2,000,000		21,000,000	4,000,000	63,000,000
Business acquisition integration related expenses	84,000,000		54,000,000	254,000,000	96,000,000
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Interest in Mitsui Sumitomo MetLife Insurance Co., LTD. ("MSI MetLife")												50.00%	50.00%
Realized gain (loss) on disposition													(57,000,000)
Net proceeds on sale of joint venture												22,500,000,000	269,000,000
Expense for reimbursement of transaction costs related to disposal of joint venture												310,000,000	4,000,000
Amount of the accumulated other comprehensive losses in the foreign currency translation adjustment component of equity, net of income tax, resulting from the hedges of the Company's investment in the joint venture were released upon sale				46,000,000
Date of disposition												April 1, 2011	April 1, 2011			November 1, 2011
Cash Consideration																180,000,000
Net investment gain (loss), net of income tax	229,000,000		(223,000,000)	221,000,000	33,000,000									0	0	(74,000,000)	0
Income from operations of discontinued operations, net of income tax														(11,000,000)	2,000,000	3,000,000	9,000,000
Negative Value of Business Acquired
Negative VOBA								4,400,000,000
Weighted average amortization period for negative VOBA						6 years
Estimated future amortization for the negative value of business acquired acquired for 2011						711,000,000
Estimated future amortization for the negative value of business acquired acquired for 2012						628,000,000
Estimated future amortization for the negative value of business acquired acquired for 2013						561,000,000
Estimated future amortization for the negative value of business acquired acquired for 2014						475,000,000
Estimated future amortization for the negative value of business acquired acquired for 2015						385,000,000
Current and Deferred Income Tax
U.S. deferred tax asset related to the reversal of temporary differences of American Life's foreign branches	671,000,000			671,000,000
U.S. deferred tax asset valuation allowance recorded related to the reversal of temporary differences of American Life's foreign branches	$ 671,000,000			$ 671,000,000