Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Operating activities
Net income (loss)	$ 285.0	$ 452.1
Net cash provided by (used in) operating activities	1,589.1	1,176.4
Investing activities
Fixed maturities available-for-sale and equity securities with intent to hold: Purchases	(3,190.1)	(2,886.7)
Fixed maturities available-for-sale and equity securities with intent to hold: Sales	582.4	342.6
Fixed maturities available-for-sale and equity securities with intent to hold: Maturities	1,984.1	1,548.9
Mortgage loans acquired or originated	(827.3)	(625.1)
Mortgage loans sold or repaid	581.6	382.4
Real estate acquired	(39.6)	(10.5)
Net purchases of property and equipment	(18.0)	(29.4)
Net change in other investments	14.2	(213.3)
Net cash provided by (used in) investing activities	(912.7)	(1,491.1)
Financing activities
Issuance of common stock	9.0	5.8
Acquisition of treasury stock	(231.8)	(153.6)
Payments for financing element derivatives	(7.1)	(6.5)
Purchase of subsidiary shares from noncontrolling interest	(0.9)
Dividends to common stockholders	(153.6)	(150.2)
Issuance of long-term debt		6.7
Principal repayments of long-term debt	(64.5)	(0.3)
Net proceeds from (repayments of) short-term borrowings	24.6	0.1
Investment contract deposits	2,725.7	1,872.2
Investment contract withdrawals	(2,255.6)	(1,947.4)
Net increase (decrease) in banking operation deposits	244.5	(35.4)
Other	0.1	5.5
Net cash provided by (used in) financing activities	290.4	(403.1)
Net increase (decrease) in cash and cash equivalents	966.8	(717.8)
Cash and cash equivalents at beginning of period	2,515.9	2,977.5
Cash and cash equivalents at end of period	3,482.7	2,259.7
Supplemental disclosure of non-cash activities:
Lease assets established upon adoption of accounting guidance		168.8
Lease liabilities established upon adoption of accounting guidance		$ 164.0
Assets received in kind from pension risk transfer transactions	$ 909.6