Contingencies and Other Matters (Details) (USD $)	1 Months Ended	3 Months Ended	9 Months Ended		12 Months Ended
	Jul. 24, 2012	Dec. 31, 2009	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Contingencies And Other Matters Details [Line Items]
Guaranteed Separate Accounts Liability			$ 1,200,000,000
Separate Accounts Liability Sold Business Percent Reinsured			65.00%
Underlying mutual fund investment values for Guaranteed Minimum Income Benefits			1,100,000,000
Maximum potential undiscounted payments under Guaranteed Minimum Income Benefits assumptions			1,100,000,000
Percentage of Guaranteed Minimum Income Benefit assets reinsured externally			55.00%		55.00%
Indemnification Obligations To Lenders			294,000,000
Liabilities Required Indemnification Obligations Real Estate Joint Ventures			0
Leased equipment value deficiency guarantees			41,000,000
Guarantee For Lease Shortfall Expiring 2013			25,000,000
Guarantee For Lease Shortfall Expiring 2017			16,000,000
Guarantee Liability For Lease Shortfall			2,000,000
Guarantees to banks to settle claim checks processed by the company for administrative service only customers			389,000,000
Liabilities Required Bank Service Guarantees			0
Charges for administrative service only bank guarantees			0	0
Percent reduction in exposure of guarantees to banks since balance sheet date	89.00%
Percentage of Administrative Service Only fees at risk for performance guarantees			16.00%
Percentage of ASO fees reimbursed for performance guarantees			2.00%
Liabilities Required Indemnification Obligations Acquisitions and Dispositions			0
Estimated Potential Guaranty Fund Assessments Range			60,000,000
Litigation reserves pre tax			102,000,000
Litigation reserves after tax			66,000,000
Contribution to establishment of non-profit resulting from Ingenix		$ 10,000,000