Consolidated Statements of Comprehensive Income - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Revenues
Net premiums earned	$ 10,982.3	$ 9,648.6	$ 21,402.5	$ 19,079.3
Investment income	210.7	243.8	430.9	485.0
Net realized gains (losses) on securities:
Net realized gains (losses) on security sales	410.1	260.0	553.9	575.2
Net holding period gains (losses) on securities	54.2	630.8	495.7	(238.0)
Net impairment losses recognized in earnings	(2.5)	0.0	(2.5)	0.0
Total net realized gains (losses) on securities	461.8	890.8	1,047.1	337.2
Fees and other revenues	176.2	129.5	341.9	283.0
Service revenues	74.5	59.0	128.3	110.6
Total revenues	11,905.5	10,971.7	23,350.7	20,295.1
Expenses
Losses and loss adjustment expenses	8,406.4	5,321.4	15,516.9	11,476.6
Policy acquisition costs	928.8	795.5	1,803.2	1,578.3
Other underwriting expenses	1,440.5	1,438.9	2,921.6	2,848.8
Policyholder credit expense	0.0	1,033.4	0.0	1,033.4
Investment expenses	6.3	4.5	11.9	9.8
Service expenses	67.9	52.8	117.2	100.3
Interest expense	56.4	56.4	112.8	104.4
Total expenses	10,906.3	8,702.9	20,483.6	17,151.6
Net Income
Income before income taxes	999.2	2,268.8	2,867.1	3,143.5
Provision for income taxes	209.1	478.4	597.0	654.0
Net income	790.1	1,790.4	2,270.1	2,489.5
Other Comprehensive Income (Loss)
Total net unrealized gains (losses) on fixed-maturity securities	91.1	567.4	(448.5)	630.2
Net unrealized losses on forecasted transactions	0.3	0.2	0.5	0.4
Foreign currency translation adjustment	(0.5)	0.0	(0.5)	0.0
Other comprehensive income (loss)	90.9	567.6	(448.5)	630.6
Comprehensive income	881.0	2,358.0	1,821.6	3,120.1
Net income attributable to Progressive	790.1	1,790.4	2,270.1	2,489.5
Computation of Earnings Per Common Share
Net income attributable to Progressive	790.1	1,790.4	2,270.1	2,489.5
Less: Preferred share dividends	6.7	6.7	13.4	13.4
Net income available to common shareholders	$ 783.4	$ 1,783.7	$ 2,256.7	$ 2,476.1
Average common shares outstanding - Basic	584.6	584.8	584.7	584.8
Net effect of dilutive stock-based compensation	2.2	2.4	2.1	2.3
Total average equivalent common shares - Diluted	586.8	587.2	586.8	587.1
Basic: Earnings per common share	$ 1.34	$ 3.05	$ 3.86	$ 4.23
Diluted: Earnings per common share	$ 1.34	$ 3.04	$ 3.85	$ 4.22