Condensed Consolidated Statements of Cash Flows (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Statement of Cash Flows [Abstract]
Net cash provided by operating activities	$ 2,916.2	$ 2,942.1
Proceeds from the sale, maturity, disposal or redemption of:
Fixed maturities	9,192.3	11,626.7
Equity securities, available-for-sale	63.7	47.1
Mortgage loans on real estate	937.6	1,253.5
Limited partnerships/corporations	137.6	274.8
Acquisition of:
Fixed maturities	(9,172.3)	(14,281.7)
Equity securities, available-for-sale	(18.3)	(17.9)
Mortgage loans on real estate	(1,574.8)	(1,583.2)
Limited partnerships/corporations	(261.3)	(81.0)
Short-term investments, net	(124.5)	3,443.2
Policy loans, net	42.8	52.8
Derivatives, net	(670.7)	(1,981.6)
Other investments, net	38.5	34.3
Sales from consolidated investment entities	2,558.5	2,518.7
Purchases within consolidated investment entities	(4,292.6)	(3,352.2)
Collateral received (delivered), net	116.8	(751.5)
Purchases of fixed assets, net	(26.5)	(25.7)
Net cash used in investing activities	(3,053.2)	(2,823.7)
Cash Flows from Financing Activities:
Deposits received for investment contracts	5,681.5	8,985.2
Maturities and withdrawals from investment contracts	(7,332.9)	(9,648.9)
Proceeds from issuance of debt with maturities of more than three months	0	2,147.1
Repayment of debt with maturities of more than three months	0	(2,697.4)
Short-term debt, net	0	(171.6)
Debt issuance costs	(16.8)	(24.8)
Borrowings of consolidated investment entities	340.5	32.0
Repayments of borrowings of consolidated investment entities	(66.6)	(8.5)
Contributions from (distributions to) participants in consolidated investment entities, net	1,235.9	626.7
Proceeds from issuance of common stock, net	0	571.6
Common stock acquired - Share repurchase	(614.4)	0
Share-based compensation	(14.8)	0
Dividends paid	(7.7)	0
Net cash used in financing activities	(795.3)	(188.6)
Net decrease in cash and cash equivalents	(932.3)	(70.2)
Cash and cash equivalents, beginning of year	2,840.8	1,786.8
Cash and cash equivalents, end of year	1,908.5	1,716.6
Supplemental cash flow information:
Income taxes paid (received), net	44.4	(2.8)
Interest paid	$ 156.9	$ 126.3