Consolidated Statements of Comprehensive Income - USD ($) shares in Millions, $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Revenues
Net premiums earned		$ 6,313.3	$ 5,561.8	$ 12,340.0	$ 10,879.2
Period over prior year period percent change in net premiums earned		14.00%		13.00%
Investment income		$ 138.8	114.6	$ 268.0	233.4
Period over prior year period percent change in investment income		21.00%		15.00%
Net realized gains (losses) on securities:
Net impairment losses recognized in earnings		$ (13.8)	(0.2)	$ (14.8)	(0.2)
Net realized gains (losses) on securities		$ 45.9	32.5	$ 98.8	49.9
Period over prior year period percent change in net realized gains (losses) on securities		41.00%		98.00%
Total net realized gains (losses) on securities		$ 32.1	32.3	$ 84.0	49.7
Period over prior year period percent change in total net realized gains (losses) on securities		(1.00%)		69.00%
Fees and other revenues		$ 88.8	82.5	$ 174.0	161.4
Period over prior year period percent change in fees and other revenues		8.00%		8.00%
Service revenues		$ 32.7	26.5	$ 61.2	51.5
Period over prior year period percent change in service revenues		23.00%		19.00%
Gains on extinguishment of debt		$ 0.0	1.6	$ 0.2	1.6
Percent Increase (Decrease) Gain Loss on Extingiushment of Debt		(100.00%)		(88.00%)
Total revenues		$ 6,605.7	5,819.3	$ 12,927.4	11,376.8
Period over prior year period percent change in total revenues		14.00%		14.00%
Expenses
Losses and loss adjustment expenses		$ 4,614.9	4,243.0	$ 8,878.3	8,156.4
Period over prior year period percent change in losses and loss adjustment expenses		9.00%		9.00%
Policy acquisition costs		$ 514.2	458.9	$ 1,017.1	899.2
Period over prior year period percent change in policy acquisition costs		12.00%		13.00%
Other underwriting expenses		$ 845.0	766.8	$ 1,690.6	1,522.6
Period over prior year period percent change in other underwriting expenses		10.00%		11.00%
Investment expenses		$ 6.6	5.3	$ 12.2	10.1
Period over prior year period percent change in investment expenses		25.00%		21.00%
Service expenses		$ 27.0	23.7	$ 52.9	45.3
Period over prior year period percent change in service expenses		14.00%		17.00%
Interest expense		$ 43.4	34.3	$ 80.2	68.5
Period over prior year period percent change in interest expense		27.00%		17.00%
Total expenses		$ 6,051.1	5,532.0	$ 11,731.3	10,702.1
Period over prior year period percent change in total expenses		9.00%		10.00%
Net Income
Income before income taxes		$ 554.6	287.3	$ 1,196.1	674.7
Period over prior year period percent change in income before income taxes		93.00%		77.00%
Provision for income taxes		$ 181.9	92.4	$ 393.1	221.1
Period over prior year period percent change in provision for income taxes		97.00%		78.00%
Net income		$ 372.7	194.9	$ 803.0	453.6
Period over prior year period percent change in net income		91.00%		77.00%
Net (income) loss attributable to noncontrolling interest (NCI)		$ (5.1)	(4.0)	$ (11.1)	(4.5)
Period over prior year period percent change in net (income) loss attributable to noncontrolling interest		28.00%		147.00%
Net income attributable to Progressive		$ 367.6	190.9	$ 791.9	449.1
Period over prior year period percent change in net income attributable to Progressive		93.00%		76.00%
Other Comprehensive Income (Loss)
Total net unrealized gains (losses) on securities		$ 92.6	91.6	$ 225.0	161.1
Period over prior year period percent change in total net unrealized gains (losses) on securities		1.00%		40.00%
Net unrealized losses on forecasted transactions		$ (8.0)	(0.3)	$ (5.7)	(0.6)
Foreign currency translation adjustment		$ (0.1)	(0.1)	$ 0.2	0.4
Period over prior year period percent change in foreign currency translation adjustment		0.00%		(50.00%)
Other comprehensive income		$ 84.5	91.2	$ 219.5	160.9
Period over prior year period percent change in other comprehensive income		(7.00%)		36.00%
Other comprehensive (income) loss attributable to NCI		$ (1.3)	(1.4)	$ (2.2)	(3.5)
Period over prior year period change in Comprehensive (income) loss attributable to NCI		(7.00%)		(37.00%)
Comprehensive income attributable to Progressive		$ 450.8	$ 280.7	$ 1,009.2	$ 606.5
Period over prior year period percent change in comprehensive income		61.00%		66.00%
Computation of Per Share Earnings Attributable to Progressive
Average shares outstanding - Basic		580.5	582.4	580.4	582.8
Period over prior year period percent change in average shares outstanding - basic		0.00%		0.00%
Net effect of dilutive stock-based compensation		3.3	2.7	3.1	2.5
Period over prior year period percent change in net effect of dilutive stock-based compensation		22.00%		24.00%
Total average equivalent shares - Diluted		583.8	585.1	583.5	585.3
Period over prior year period percent change in total equivalent shares - diluted		0.00%		0.00%
Basic: Earnings per share		$ 0.63	$ 0.33	$ 1.36	$ 0.77
Period over prior year period percent change in basic: earnings per share		93.00%		77.00%
Diluted: Earnings per share		$ 0.63	0.33	$ 1.36	0.77
Period over prior year period percent change in diluted: earnings per share		93.00%		77.00%
Dividends declared per share	[1]	$ 0	$ 0	$ 0	$ 0

[1] Progressive maintains an annual dividend program. See Note 9 – Dividends for further discussion.