Consolidated Statements of Cash Flows (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Operating activities
Net income (loss)	$ 190.0	$ 221.3
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Amortization of deferred acquisition costs	55.6	(129.3)
Additions to deferred acquisition costs	(124.2)	(99.6)
Accrued investment income	(0.1)	(7.3)
Net cash flows for trading securities	(122.1)	7.0
Premiums due and other receivables	8.7	97.3
Contractholder and policyholder liabilities and dividends	133.1	521.9
Current and deferred income taxes (benefits)	136.5	(32.6)
Net realized capital (gains) losses	50.9	6.7
Depreciation and amortization expense	34.9	32.8
Mortgage loans held for sale, acquired or originated		(22.0)
Mortgage loans held for sale, sold or repaid, net of gain		24.0
Real estate acquired through operating activities	(16.7)	(2.9)
Real estate sold through operating activities	10.2	1.2
Stock-based compensation	19.4	25.1
Other	219.7	258.1
Net adjustments	405.9	680.4
Net cash provided by (used in) operating activities	595.9	901.7
Investing activities
Available-for-sale securities: Purchases	(2,447.1)	(2,060.5)
Available-for-sale securities: Sales	503.1	428.5
Available-for-sale securities: Maturities	1,790.9	1,612.1
Mortgage loans acquired or originated	(610.9)	(919.6)
Mortgage loans sold or repaid	555.8	361.4
Real estate acquired	(23.4)	(21.3)
Net (purchases) sales of property and equipment	6.7	(17.3)
Purchases of interest in subsidiaries, net of cash acquired	(1,268.3)
Net change in other investments	(32.2)	(73.8)
Net cash provided by (used in) investing activities	(1,525.4)	(690.5)
Financing activities
Issuance of common stock	20.3	9.1
Acquisition of treasury stock	(90.9)	(64.2)
Proceeds from financing element derivatives	14.3	20.4
Payments for financing element derivatives	(12.7)	(16.2)
Excess tax benefits from share-based payment arrangements	3.8	9.9
Purchase of subsidiary shares from noncontrolling interest	(30.6)
Dividends to common stockholders	(67.6)	(54.3)
Dividends to preferred stockholders		(8.2)
Issuance of long-term debt	3.5	1.0
Principal repayments of long-term debt	(0.4)	(0.8)
Net proceeds from (repayments of) short-term borrowings		(7.5)
Investment contract deposits	1,419.7	1,618.6
Investment contract withdrawals	(2,852.0)	(2,885.9)
Net increase (decrease) in banking operation deposits	6.9	(13.4)
Other	(0.8)	(1.7)
Net cash provided by (used in) financing activities	(1,586.5)	(1,393.2)
Net increase (decrease) in cash and cash equivalents	(2,516.0)	(1,182.0)
Cash and cash equivalents at beginning of period	4,177.2	2,833.9
Cash and cash equivalents at end of period	$ 1,661.2	$ 1,651.9