Consolidated Statements of Comprehensive Income - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Revenues
Net premiums earned	$ 10,420.2	$ 9,430.7
Investment income	220.2	241.2
Net realized gains (losses) on securities:
Net realized gains (losses) on security sales	143.8	315.2
Net holding period gains (losses) on securities	441.5	(868.8)
Total net realized gains (losses) on securities	585.3	(553.6)
Fees and other revenues	165.7	153.5
Service revenues	53.8	51.6
Total revenues	11,445.2	9,323.4
Expenses
Losses and loss adjustment expenses	7,110.5	6,155.2
Policy acquisition costs	874.4	782.8
Other underwriting expenses	1,481.1	1,409.9
Investment expenses	5.6	5.3
Service expenses	49.3	47.5
Interest expense	56.4	48.0
Total expenses	9,577.3	8,448.7
Net Income
Income before income taxes	1,867.9	874.7
Provision for income taxes	387.9	175.6
Net income	1,480.0	699.1
Net income attributable to noncontrolling interest (NCI)	0.0	(6.4)
Net income attributable to Progressive	1,480.0	692.7
Other Comprehensive Income (Loss)
Total net unrealized gains (losses) on fixed-maturity securities	(539.6)	62.8
Net unrealized losses on forecasted transactions	0.2	0.2
Other comprehensive income (loss)	(539.4)	63.0
Other comprehensive income attributable to NCI	0.0	(0.5)
Comprehensive income attributable to Progressive	940.6	755.2
Computation of Earnings Per Common Share
Net income attributable to Progressive	1,480.0	692.7
Less: Preferred share dividends	6.7	6.7
Net income available to common shareholders	$ 1,473.3	$ 686.0
Average common shares outstanding - Basic	584.9	584.7
Net effect of dilutive stock-based compensation	2.0	2.2
Total average equivalent common shares - Diluted	586.9	586.9
Basic: Earnings per common share	$ 2.52	$ 1.17
Diluted: Earnings per common share	$ 2.51	$ 1.17