CONSOLIDATED BALANCE SHEET (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Investments:
Fixed maturities, available for sale, allowance for credit losses	$ 7.6	$ 2.1
Fixed maturities, available for sale, amortized cost	19,783.3	19,179.5
Mortgage loans, allowance for credit losses	12.2	6.7
Investments held by variable interest entities, allowance for credit losses	22.2
Investments held by variable interest entities, amortized cost	1,223.7	$ 1,206.3
Reinsurance receivables, allowance for current expected credit losses	$ 4.0
Shareholders' equity:
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	8,000,000,000	8,000,000,000
Common stock, shares issued (in shares)	138,931,352	148,084,178
Common stock, shares outstanding (in shares)	138,931,352	148,084,178