Shareholders' Equity and Dividend Availability (details) (USD $) In Billions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Jun. 07, 2011
Shareholders' Equity and Dividend Availability disclosure
Common stock, shares authorized	1,750,000,000	1,750,000,000
Number of authorized shares, voting common stock	1,745,000,000
Number of authorized shares, undesignated shares	5,000,000
Number of common shares issued upon conversion of preferred shares, per preferred share				8
Preferred shares outstanding				190,083
Number of common shares issued upon conversion of preferred shares, total				1,520,000
Maximum amount of dividends available to be paid by subsidiaries to their parent without prior approval of the Connecticut Insurance Department	$ 2.05
Dividends received by holding company from its domestic insurance subsidiaries	1.96
Statutory net income of the Company's domestic and international insurance subsidiaries	2.84	1.50	3.69
Policyholder surplus of the Company's domestic and international insurance subsidiaries	$ 20.05	$ 19.17