STATUTORY REPORTING PRACTICES AND OTHER REGULATORY MATTERS (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
STATUTORY REPORTING PRACTICES AND OTHER REGULATORY MATTERS
Statutory net income	$ 376,300,000	$ 259,200,000	$ 303,600,000
Statutory capital and surplus	3,000,000,000	2,600,000,000
Shareowners' equity, excluding net unrealized gains on investments	633,000,000
Period for which dividend can be paid after written notice to the insurance commissioner	30 days
Dividends receivable from subsidiaries	95,000,000
Total adjusted capital	3,300,000,000
Action level RBC	644,000,000
RBC ratio (as a percent)	510.00%
Market value of fixed maturity and short-term investments of the company's subsidiaries deposited with regulatory authorities	$ 48,700,000