Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Operating activities
Net cash provided by (used in) operating activities	$ 2,107.0	$ 3,110.4
Investing activities
Fixed maturities available-for-sale and equity securities with intent to hold: Purchases	(11,065.1)	(12,060.6)
Fixed maturities available-for-sale and equity securities with intent to hold: Sales	2,383.5	2,677.3
Fixed maturities available-for-sale and equity securities with intent to hold: Maturities	8,162.3	6,247.7
Mortgage loans acquired or originated	(4,277.1)	(2,281.7)
Mortgage loans sold or repaid	2,142.3	1,877.0
Real estate acquired	(187.8)	(177.1)
Real estate sold	43.5
Net (purchases) sales of property and equipment	(108.9)	(82.9)
Net change in other investments	40.0	160.4
Net cash provided by (used in) investing activities	(2,867.3)	(3,639.9)
Financing activities
Issuance of common stock	57.3	34.6
Acquisition of treasury stock	(585.1)	(232.0)
Payments for financing element derivatives	(27.6)	(22.2)
Purchase of subsidiary shares from noncontrolling interest	(24.2)	(0.9)
Dividends to common stockholders	(485.6)	(460.8)
Issuance of long-term debt		608.8
Principal repayments of long-term debt	(1.4)	(65.3)
Net proceeds from (repayments of) short-term borrowings	0.2	(12.3)
Investment contract deposits	7,341.8	7,798.7
Investment contract withdrawals	(6,566.4)	(6,520.3)
Net increase (decrease) in banking operation deposits	1,346.9	441.8
Other		0.2
Net cash provided by (used in) financing activities	1,055.9	1,570.3
Net increase (decrease) in cash and cash equivalents	295.6	1,040.8
Cash and cash equivalents at beginning of period	2,849.8	2,515.9
Cash and cash equivalents at end of period	3,145.4	3,556.7
Changes from re-designation of other postretirement employee benefits ("OPEB") plan assets to cover non-retiree benefits:
Increases in equity securities re-designated from funded status of OPEB plan	548.1
Increases in other investments re-designated from funded status of OPEB plan	117.5
Decrease in tax receivable re-designated from funded status of OPEB plan	(9.1)
Decrease in accumulated other comprehensive income ("AOCI") due to reclassifying excess assets out of funded status of OPEB plan	9.1
Decrease in other assets due to reclassifying excess assets out of funded status of OPEB plan	(665.6)
Assets received in kind from pension risk transfer transactions	$ 109.5	$ 1,062.4