Consolidated Balance Sheets - USD ($) $ in Millions		Jun. 30, 2022	Dec. 31, 2021	Jun. 30, 2021
Assets
Fixed maturities (amortized cost: $46,028.8, $42,378.0, and $43,794.2)		$ 43,172.5	$ 43,873.1	$ 43,031.0
Short-term investments (amortized cost: $4,611.8, $1,710.6, and $942.6)		4,611.8	942.6	1,710.6
Total available-for-sale securities		47,784.3	44,815.7	44,741.6
Nonredeemable preferred stocks (cost: $1,522.5, $1,511.2, and $1,571.8)		1,360.5	1,639.9	1,609.8
Common equities (cost: $783.6, $1,238.4, and $1,264.1)		2,784.7	5,058.5	4,591.4
Total equity securities		4,145.2	6,698.4	6,201.2
Total investments		51,929.5	51,514.1	50,942.8
Cash and cash equivalents		226.1	187.1	99.5
Restricted cash and cash equivalents		14.4	15.0	15.1
Total cash, cash equivalents, restricted cash, and restricted cash equivalents		240.5	202.1	114.6
Accrued investment income		216.7	181.7	179.3
Premiums receivable, net of allowance for credit losses of $265.8, $245.2, and $280.4		10,561.8	9,399.5	9,436.2
Reinsurance recoverables		4,961.2	4,980.5	4,709.1
Prepaid reinsurance premiums		464.3	457.6	620.0
Deferred acquisition costs		1,498.4	1,355.6	1,360.6
Property and equipment, net of accumulated depreciation of $1,512.6, $1,396.5, and $1,407.4		1,124.7	1,137.3	1,086.4
Goodwill		227.9	452.7	452.7
Intangible assets, net of accumulated amortization of $147.7, $354.6, and $383.8		97.2	117.3	146.5
Net federal deferred income taxes		955.6	0.0	0.0
Other assets		779.4	1,333.9	776.1
Total assets		73,057.2	71,132.3	69,824.3
Liabilities
Unearned premiums		17,274.8	15,615.8	15,555.9
Loss and loss adjustment expense reserves		27,812.0	26,164.1	23,895.6
Net federal deferred income taxes		0.0	152.9	219.4
Accounts payable, accrued expenses, and other liabilities		5,931.2	6,069.1	6,080.3
Debt	[1]	6,386.5	4,898.8	5,397.5
Total liabilities		57,404.5	52,900.7	51,148.7
Shareholders' Equity
Serial Preferred Shares, Series B, no par value (cumulative, liquidation preference $1,000 per share) (authorized, issued, and outstanding 0.5)		493.9	493.9	493.9
Common shares, $1.00 par value (authorized 900.0; issued 797.6, including treasury shares of 212.7, 212.4, and 213.2)		584.9	584.4	585.2
Paid-in capital		1,815.2	1,772.9	1,712.3
Retained earnings		14,967.7	15,339.7	15,401.0
Accumulated other comprehensive income (loss):
Net unrealized gains (losses) on fixed-maturity securities		(2,193.5)	56.2	498.8
Net unrealized losses on forecasted transactions		(14.7)	(14.9)	(15.1)
Foreign currency translation adjustment		(0.8)	(0.6)	(0.5)
Total accumulated other comprehensive income (loss)		(2,209.0)	40.7	483.2
Total shareholders’ equity		15,652.7	18,231.6	18,675.6
Total liabilities and shareholders’ equity		$ 73,057.2	$ 71,132.3	$ 69,824.3

[1] Consists of long-term debt. See Note 4 – Debt for further discussion.