Liability for Future Policy Benefit Activity (Details) - USD ($) $ in Millions		9 Months Ended
		Sep. 30, 2023		Sep. 30, 2022		Dec. 31, 2022		Dec. 31, 2021	Jan. 01, 2021
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Future Policy Benefits		$ 36,502.4		$ 37,808.0	[1]	$ 38,577.1	[2]
Operating Segments
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Liability for Future Policy Benefit, Expected Net Premium, before Reinsurance, after Discount Rate Change, balance beginning of year		12,426.2		15,881.3
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Cash Flow and Reinsurance, balance at beginning of period		12,695.3		13,186.2
Liability for Future Policy Benefit, Expected Net Premium, Cumulative Increase (Decrease) from Cash Flow Change						1,499.2		$ (101.9)
Liability for Future Policy Benefit, Expected Net Premium, Cumulative Increase (Decrease) of Actual Variance from Expected Experience						(121.8)		(252.3)
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Reinsurance, after Cash Flow Change						14,072.7		12,832.0
Liability for Future Policy Benefit, Expected Net Premium, Issuance		861.2		727.2
Liability for Future Policy Benefit, Expected Net Premium, Interest Income		430.8		430.0
Liability for Future Policy Benefit, Expected Net Premium, Net Premium Collected		(1,164.9)		(1,184.1)
Liability for Future Policy Benefit, Expected Net Premium, Increase (Decrease) for Other Change		(0.1)		(49.5)
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Cash Flow and Reinsurance, balance at end of period		14,199.7		12,755.6
AOCI, Liability for Future Policy Benefit, Expected Net Premium, before Tax		(709.0)		(418.5)
Liability for Future Policy Benefit, Expected Net Premium, before Reinsurance, after Discount Rate Change		13,490.7		12,337.1
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Liability for Future Policy Benefit, Expected Future Policy Benefit, before Reinsurance, after Discount Rate Change, beginning of year		48,929.4		65,305.0
Liability for Future Policy Benefit, Expected Future Policy Benefit, Original Discount Rate, before Cash Flow and Reinsurance, beginning of period		49,689.0		50,397.2
Liability for Future Policy Benefit, Expected Future Policy Benefit, Cumulative Increase (Decrease) from Cash Flow Change						1,702.0		(92.4)
Liability for Future Policy Benefit, Expected Future Policy Benefit, Cumulative Increase (Decrease) of Actual Variance from Expected Experience						(356.4)		(459.6)
Liability for Future Policy Benefit, Expected Future Benefit, Original Discount Rate, before Reinsurance, after Cash Flow Change						$ 51,034.6		$ 49,845.2
Liability for Future Policy Benefit, Expected Future Policy Benefit, Issuance	[3]	2,547.0		2,602.7
Liability for Future Policy Benefit, Expected Future Policy Benefit, Interest Expense		1,670.3		1,689.3
Liability for Future Policy Benefit, Expected Future Policy Benefit, Benefit Payment		(4,106.1)		(4,112.1)
Liability for Future Policy Benefit, Expected Future Policy Benefit, Increase (Decrease) for Other Change		19.6		(485.7)
Liability for Future Policy Benefit, Expected Future Policy Benefit, Original Discount Rate, before Cash Flow and Reinsurance, end of period		51,165.4		49,539.4
AOCI, Liability for Future Policy Benefit, Expected Future Policy Benefit, before Tax		(3,111.7)		(1,484.8)
Liability for Future Policy Benefit, Expected Future Policy Benefit, before Reinsurance, after Discount Rate Change, end of year		48,053.7		48,054.6
Liability for Future Policy Benefit, before Reinsurance, before Other		34,563.0		35,717.5
Liability for Future Policy Benefits, Other Contracts		1,703.3		1,872.7
Liability for Future Policy Benefit, before Reinsurance, after Other		36,266.3		37,590.2					$ 55,585.4
Liability for Future Policy Benefit, Reinsurance Recoverable, after Allowance		7,449.0		8,154.6					10,496.0	[4]
Liability for Future Policy Benefit, after Reinsurance		28,817.3		29,435.6					45,089.4
Liability for Future Policy Benefit, Gross Premium Income		7,278.4		7,033.8
Liability for Future Policy Benefit, Expected Future Policy Benefit, Interest Expense		1,239.5		1,259.3
Liability for Future Policy Benefit, Expected Future Policy Benefit, Undiscounted, before Reinsurance		105,306.1		97,202.5
Liability for Future Policy Benefit, Expected Future Gross Premium, Undiscounted, before Reinsurance		38,581.4		35,301.8
Liability for Future Policy Benefit, Expected Future Gross Premium, Discounted, before Reinsurance		$ 25,435.2		$ 23,835.8
Liability for Future Policy Benefit, Weighted-Average Interest Accretion Rate		4.80%		4.80%
Liability for Future Policy Benefit, Current Weighted-Average Discount Rate		5.60%		5.20%		5.00%		2.50%
Liability for Future Policy Benefit, Weighted-Average Duration		11 years 6 months		11 years
Future Policy Benefits		$ 36,502.4		$ 37,808.0
Unum US
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Liability for Future Policy Benefit, Expected Net Premium, before Reinsurance, after Discount Rate Change, balance beginning of year		2,071.1		2,619.1
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Cash Flow and Reinsurance, balance at beginning of period		2,166.0		2,311.9
Liability for Future Policy Benefit, Expected Net Premium, Cumulative Increase (Decrease) from Cash Flow Change						$ 185.7		$ (97.1)
Liability for Future Policy Benefit, Expected Net Premium, Cumulative Increase (Decrease) of Actual Variance from Expected Experience						(111.8)		(117.1)
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Reinsurance, after Cash Flow Change						2,239.9		2,097.7
Liability for Future Policy Benefit, Expected Net Premium, Issuance		422.6		249.5
Liability for Future Policy Benefit, Expected Net Premium, Interest Income		57.7		60.5
Liability for Future Policy Benefit, Expected Net Premium, Net Premium Collected		(255.9)		(259.1)
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Cash Flow and Reinsurance, balance at end of period		2,464.3		2,148.6
AOCI, Liability for Future Policy Benefit, Expected Net Premium, before Tax		(181.6)		(116.6)
Liability for Future Policy Benefit, Expected Net Premium, before Reinsurance, after Discount Rate Change		2,282.7		2,032.0
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Liability for Future Policy Benefit, Expected Future Policy Benefit, before Reinsurance, after Discount Rate Change, beginning of year		11,698.2		14,564.4
Liability for Future Policy Benefit, Expected Future Policy Benefit, Original Discount Rate, before Cash Flow and Reinsurance, beginning of period		12,177.3		12,671.7
Liability for Future Policy Benefit, Expected Future Policy Benefit, Cumulative Increase (Decrease) from Cash Flow Change						77.8		(228.2)
Liability for Future Policy Benefit, Expected Future Policy Benefit, Cumulative Increase (Decrease) of Actual Variance from Expected Experience						(367.9)		(328.5)
Liability for Future Policy Benefit, Expected Future Benefit, Original Discount Rate, before Reinsurance, after Cash Flow Change						11,887.2		12,115.0
Liability for Future Policy Benefit, Expected Future Policy Benefit, Issuance		1,707.4		1,688.0
Liability for Future Policy Benefit, Expected Future Policy Benefit, Interest Expense		340.9		363.1
Liability for Future Policy Benefit, Expected Future Policy Benefit, Benefit Payment		(1,936.3)		(1,993.1)
Liability for Future Policy Benefit, Expected Future Policy Benefit, Original Discount Rate, before Cash Flow and Reinsurance, end of period		11,999.2		12,173.0
AOCI, Liability for Future Policy Benefit, Expected Future Policy Benefit, before Tax		(816.4)		(580.3)
Liability for Future Policy Benefit, Expected Future Policy Benefit, before Reinsurance, after Discount Rate Change, end of year		11,182.8		11,592.7
Liability for Future Policy Benefit, before Reinsurance, before Other		8,900.1		9,560.7
Liability for Future Policy Benefits, Other Contracts		29.9		41.2
Liability for Future Policy Benefit, before Reinsurance, after Other		8,930.0		9,601.9					12,861.4
Liability for Future Policy Benefit, Reinsurance Recoverable, after Allowance		200.3		255.9					357.7	[4]
Liability for Future Policy Benefit, after Reinsurance		8,729.7		9,346.0					12,503.7
Liability for Future Policy Benefit, Gross Premium Income		4,679.9		4,499.5
Liability for Future Policy Benefit, Expected Future Policy Benefit, Interest Expense		283.2		302.6
Liability for Future Policy Benefit, Expected Future Policy Benefit, Undiscounted, before Reinsurance		17,943.5		17,869.4
Liability for Future Policy Benefit, Expected Future Gross Premium, Undiscounted, before Reinsurance		11,019.3		9,468.4
Liability for Future Policy Benefit, Expected Future Gross Premium, Discounted, before Reinsurance		$ 7,763.3		$ 6,886.3
Liability for Future Policy Benefit, Weighted-Average Interest Accretion Rate		4.20%		4.10%
Liability for Future Policy Benefit, Current Weighted-Average Discount Rate		5.30%		4.90%
Liability for Future Policy Benefit, Weighted-Average Duration		6 years 10 months 24 days		6 years 9 months 18 days
Future Policy Benefits	[5]	$ 8,930.0		$ 9,601.9
Unum International
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Liability for Future Policy Benefit, Expected Net Premium, before Reinsurance, after Discount Rate Change, balance beginning of year		197.1		260.5
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Cash Flow and Reinsurance, balance at beginning of period		246.8		258.1
Liability for Future Policy Benefit, Expected Net Premium, Cumulative Increase (Decrease) from Cash Flow Change						(5.1)		(0.3)
Liability for Future Policy Benefit, Expected Net Premium, Cumulative Increase (Decrease) of Actual Variance from Expected Experience						12.2		5.4
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Reinsurance, after Cash Flow Change						253.9		263.2
Liability for Future Policy Benefit, Expected Net Premium, Issuance		16.9		13.4
Liability for Future Policy Benefit, Expected Net Premium, Interest Income		6.9		6.5
Liability for Future Policy Benefit, Expected Net Premium, Net Premium Collected		(16.9)		(17.3)
Liability for Future Policy Benefit, Expected Net Premium, Increase (Decrease) for Other Change		(0.1)		(49.5)
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Cash Flow and Reinsurance, balance at end of period		260.7		216.3
AOCI, Liability for Future Policy Benefit, Expected Net Premium, before Tax		(37.6)		(46.9)
Liability for Future Policy Benefit, Expected Net Premium, before Reinsurance, after Discount Rate Change		223.1		169.4
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Liability for Future Policy Benefit, Expected Future Policy Benefit, before Reinsurance, after Discount Rate Change, beginning of year		2,231.4		3,181.8
Liability for Future Policy Benefit, Expected Future Policy Benefit, Original Discount Rate, before Cash Flow and Reinsurance, beginning of period		2,495.5		2,703.8
Liability for Future Policy Benefit, Expected Future Policy Benefit, Cumulative Increase (Decrease) from Cash Flow Change						17.7		(20.1)
Liability for Future Policy Benefit, Expected Future Policy Benefit, Cumulative Increase (Decrease) of Actual Variance from Expected Experience						(9.2)		23.5
Liability for Future Policy Benefit, Expected Future Benefit, Original Discount Rate, before Reinsurance, after Cash Flow Change						2,504.0		2,707.2
Liability for Future Policy Benefit, Expected Future Policy Benefit, Issuance	[6]	277.3		287.9
Liability for Future Policy Benefit, Expected Future Policy Benefit, Interest Expense		47.7		50.0
Liability for Future Policy Benefit, Expected Future Policy Benefit, Benefit Payment		(307.5)		(270.3)
Liability for Future Policy Benefit, Expected Future Policy Benefit, Increase (Decrease) for Other Change		19.6		(485.7)
Liability for Future Policy Benefit, Expected Future Policy Benefit, Original Discount Rate, before Cash Flow and Reinsurance, end of period		2,541.1		2,289.1
AOCI, Liability for Future Policy Benefit, Expected Future Policy Benefit, before Tax		(297.1)		(345.4)
Liability for Future Policy Benefit, Expected Future Policy Benefit, before Reinsurance, after Discount Rate Change, end of year		2,244.0		1,943.7
Liability for Future Policy Benefit, before Reinsurance, before Other		2,020.9		1,774.3
Liability for Future Policy Benefits, Other Contracts		30.3		24.9
Liability for Future Policy Benefit, before Reinsurance, after Other		2,051.2		1,799.2					3,203.4
Liability for Future Policy Benefit, Reinsurance Recoverable, after Allowance		69.4		57.8					132.5	[4]
Liability for Future Policy Benefit, after Reinsurance		1,981.8		1,741.4					3,070.9
Liability for Future Policy Benefit, Gross Premium Income		667.7		590.4
Liability for Future Policy Benefit, Expected Future Policy Benefit, Interest Expense		40.8		43.5
Liability for Future Policy Benefit, Expected Future Policy Benefit, Undiscounted, before Reinsurance		4,012.8		3,642.0
Liability for Future Policy Benefit, Expected Future Gross Premium, Undiscounted, before Reinsurance		1,035.7		814.9
Liability for Future Policy Benefit, Expected Future Gross Premium, Discounted, before Reinsurance		$ 676.8		$ 545.1
Liability for Future Policy Benefit, Weighted-Average Interest Accretion Rate		4.00%		3.90%
Liability for Future Policy Benefit, Current Weighted-Average Discount Rate		5.40%		5.90%
Liability for Future Policy Benefit, Weighted-Average Duration		8 years 7 months 6 days		8 years 6 months
Future Policy Benefits		$ 2,051.2		$ 1,799.2
Colonial Life
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Liability for Future Policy Benefit, Expected Net Premium, before Reinsurance, after Discount Rate Change, balance beginning of year		3,745.4		4,597.0
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Cash Flow and Reinsurance, balance at beginning of period		4,046.4		4,158.9
Liability for Future Policy Benefit, Expected Net Premium, Cumulative Increase (Decrease) from Cash Flow Change						(322.7)		(32.3)
Liability for Future Policy Benefit, Expected Net Premium, Cumulative Increase (Decrease) of Actual Variance from Expected Experience						(77.1)		(105.8)
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Reinsurance, after Cash Flow Change						3,646.6		4,020.8
Liability for Future Policy Benefit, Expected Net Premium, Issuance		421.7		464.3
Liability for Future Policy Benefit, Expected Net Premium, Interest Income		94.3		99.4
Liability for Future Policy Benefit, Expected Net Premium, Net Premium Collected		(454.0)		(483.6)
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Cash Flow and Reinsurance, balance at end of period		3,708.6		4,100.9
AOCI, Liability for Future Policy Benefit, Expected Net Premium, before Tax		(348.7)		(353.2)
Liability for Future Policy Benefit, Expected Net Premium, before Reinsurance, after Discount Rate Change		3,359.9		3,747.7
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Liability for Future Policy Benefit, Expected Future Policy Benefit, before Reinsurance, after Discount Rate Change, beginning of year		5,581.1		7,054.8
Liability for Future Policy Benefit, Expected Future Policy Benefit, Original Discount Rate, before Cash Flow and Reinsurance, beginning of period		6,163.9		6,201.5
Liability for Future Policy Benefit, Expected Future Policy Benefit, Cumulative Increase (Decrease) from Cash Flow Change						(402.9)		(85.9)
Liability for Future Policy Benefit, Expected Future Policy Benefit, Cumulative Increase (Decrease) of Actual Variance from Expected Experience						(90.1)		(133.4)
Liability for Future Policy Benefit, Expected Future Benefit, Original Discount Rate, before Reinsurance, after Cash Flow Change						5,670.9		5,982.2
Liability for Future Policy Benefit, Expected Future Policy Benefit, Issuance		461.1		502.9
Liability for Future Policy Benefit, Expected Future Policy Benefit, Interest Expense		161.0		165.1
Liability for Future Policy Benefit, Expected Future Policy Benefit, Benefit Payment		(462.1)		(467.4)
Liability for Future Policy Benefit, Expected Future Policy Benefit, Original Discount Rate, before Cash Flow and Reinsurance, end of period		5,830.9		6,182.8
AOCI, Liability for Future Policy Benefit, Expected Future Policy Benefit, before Tax		(731.9)		(667.5)
Liability for Future Policy Benefit, Expected Future Policy Benefit, before Reinsurance, after Discount Rate Change, end of year		5,099.0		5,515.3
Liability for Future Policy Benefit, before Reinsurance, before Other		1,739.1		1,767.6
Liability for Future Policy Benefits, Other Contracts		24.3		23.9
Liability for Future Policy Benefit, before Reinsurance, after Other		1,763.4		1,791.5					2,528.6
Liability for Future Policy Benefit, Reinsurance Recoverable, after Allowance		0.9		1.3					4.4	[4]
Liability for Future Policy Benefit, after Reinsurance		1,762.5		1,790.2					2,524.2
Liability for Future Policy Benefit, Gross Premium Income		1,240.3		1,228.3
Liability for Future Policy Benefit, Expected Future Policy Benefit, Interest Expense		66.7		65.7
Liability for Future Policy Benefit, Expected Future Policy Benefit, Undiscounted, before Reinsurance		9,568.2		9,984.0
Liability for Future Policy Benefit, Expected Future Gross Premium, Undiscounted, before Reinsurance		11,847.5		12,205.8
Liability for Future Policy Benefit, Expected Future Gross Premium, Discounted, before Reinsurance		$ 8,684.1		$ 8,996.4
Liability for Future Policy Benefit, Weighted-Average Interest Accretion Rate		4.30%		4.40%
Liability for Future Policy Benefit, Current Weighted-Average Discount Rate		5.70%		5.30%
Liability for Future Policy Benefit, Weighted-Average Duration		16 years 10 months 24 days		17 years 10 months 24 days
Future Policy Benefits		$ 1,763.4		$ 1,791.5
Closed Block
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Liability for Future Policy Benefit, Expected Net Premium, before Reinsurance, after Discount Rate Change, balance beginning of year		6,412.6		8,404.7
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Cash Flow and Reinsurance, balance at beginning of period		6,236.1		6,457.3
Liability for Future Policy Benefit, Expected Net Premium, Cumulative Increase (Decrease) from Cash Flow Change						1,641.3		27.8
Liability for Future Policy Benefit, Expected Net Premium, Cumulative Increase (Decrease) of Actual Variance from Expected Experience						54.9		(34.8)
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Reinsurance, after Cash Flow Change						7,932.3		6,450.3
Liability for Future Policy Benefit, Expected Net Premium, Interest Income		271.9		263.6
Liability for Future Policy Benefit, Expected Net Premium, Net Premium Collected		(438.1)		(424.1)
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Cash Flow and Reinsurance, balance at end of period		7,766.1		6,289.8
AOCI, Liability for Future Policy Benefit, Expected Net Premium, before Tax		(141.1)		98.2
Liability for Future Policy Benefit, Expected Net Premium, before Reinsurance, after Discount Rate Change		7,625.0		6,388.0
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Liability for Future Policy Benefit, Expected Future Policy Benefit, before Reinsurance, after Discount Rate Change, beginning of year		29,418.7		40,504.0
Liability for Future Policy Benefit, Expected Future Policy Benefit, Original Discount Rate, before Cash Flow and Reinsurance, beginning of period		28,852.3		28,820.2
Liability for Future Policy Benefit, Expected Future Policy Benefit, Cumulative Increase (Decrease) from Cash Flow Change						2,009.4		241.8
Liability for Future Policy Benefit, Expected Future Policy Benefit, Cumulative Increase (Decrease) of Actual Variance from Expected Experience						110.8		(21.2)
Liability for Future Policy Benefit, Expected Future Benefit, Original Discount Rate, before Reinsurance, after Cash Flow Change						30,972.5		29,040.8
Liability for Future Policy Benefit, Expected Future Policy Benefit, Issuance		101.2		123.9
Liability for Future Policy Benefit, Expected Future Policy Benefit, Interest Expense		1,120.7		1,111.1
Liability for Future Policy Benefit, Expected Future Policy Benefit, Benefit Payment		(1,400.2)		(1,381.3)
Liability for Future Policy Benefit, Expected Future Policy Benefit, Original Discount Rate, before Cash Flow and Reinsurance, end of period		30,794.2		28,894.5
AOCI, Liability for Future Policy Benefit, Expected Future Policy Benefit, before Tax		(1,266.3)		108.4
Liability for Future Policy Benefit, Expected Future Policy Benefit, before Reinsurance, after Discount Rate Change, end of year		29,527.9		29,002.9
Liability for Future Policy Benefit, before Reinsurance, before Other		21,902.9		22,614.9
Liability for Future Policy Benefits, Other Contracts		1,618.8		1,782.7
Liability for Future Policy Benefit, before Reinsurance, after Other		23,521.7		24,397.6					36,992.0
Liability for Future Policy Benefit, Reinsurance Recoverable, after Allowance		7,178.3		7,839.5					10,001.4	[4]
Liability for Future Policy Benefit, after Reinsurance		16,343.4		16,558.1					26,990.6
Liability for Future Policy Benefit, Gross Premium Income		690.5		715.6
Liability for Future Policy Benefit, Expected Future Policy Benefit, Interest Expense		848.8		847.5
Liability for Future Policy Benefit, Expected Future Policy Benefit, Undiscounted, before Reinsurance		73,781.6		65,707.1
Liability for Future Policy Benefit, Expected Future Gross Premium, Undiscounted, before Reinsurance		14,678.9		12,812.7
Liability for Future Policy Benefit, Expected Future Gross Premium, Discounted, before Reinsurance		$ 8,311.0		$ 7,408.0
Liability for Future Policy Benefit, Weighted-Average Interest Accretion Rate		5.20%		5.20%
Liability for Future Policy Benefit, Current Weighted-Average Discount Rate		5.80%		5.30%
Liability for Future Policy Benefit, Weighted-Average Duration		13 years 3 months 18 days		12 years 6 months
Future Policy Benefits	[5]	$ 23,521.7		$ 24,397.6
Other Products [Member]
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Future Policy Benefits	[5]	236.1		217.8
Group Disability | Unum US
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Liability for Future Policy Benefit, Expected Net Premium, before Reinsurance, after Discount Rate Change, balance beginning of year		0.0		0.0
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Cash Flow and Reinsurance, balance at beginning of period		0.0		0.0
Liability for Future Policy Benefit, Expected Net Premium, Cumulative Increase (Decrease) from Cash Flow Change						0.0		0.0
Liability for Future Policy Benefit, Expected Net Premium, Cumulative Increase (Decrease) of Actual Variance from Expected Experience						0.0		0.0
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Reinsurance, after Cash Flow Change						0.0		0.0
Liability for Future Policy Benefit, Expected Net Premium, Issuance		0.0		0.0
Liability for Future Policy Benefit, Expected Net Premium, Interest Income		0.0		0.0
Liability for Future Policy Benefit, Expected Net Premium, Net Premium Collected		0.0		0.0
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Cash Flow and Reinsurance, balance at end of period		0.0		0.0
AOCI, Liability for Future Policy Benefit, Expected Net Premium, before Tax		0.0		0.0
Liability for Future Policy Benefit, Expected Net Premium, before Reinsurance, after Discount Rate Change		0.0		0.0
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Liability for Future Policy Benefit, Expected Future Policy Benefit, before Reinsurance, after Discount Rate Change, beginning of year		5,533.3		6,725.7
Liability for Future Policy Benefit, Expected Future Policy Benefit, Original Discount Rate, before Cash Flow and Reinsurance, beginning of period		5,793.1		6,158.3
Liability for Future Policy Benefit, Expected Future Policy Benefit, Cumulative Increase (Decrease) from Cash Flow Change						(100.2)		(102.0)
Liability for Future Policy Benefit, Expected Future Policy Benefit, Cumulative Increase (Decrease) of Actual Variance from Expected Experience						(187.8)		(174.1)
Liability for Future Policy Benefit, Expected Future Benefit, Original Discount Rate, before Reinsurance, after Cash Flow Change						5,505.1		5,882.2
Liability for Future Policy Benefit, Expected Future Policy Benefit, Issuance		907.1	[7]	1,038.9	[8]
Liability for Future Policy Benefit, Expected Future Policy Benefit, Interest Expense		137.6		162.2
Liability for Future Policy Benefit, Expected Future Policy Benefit, Benefit Payment		(1,186.8)		(1,228.7)
Liability for Future Policy Benefit, Expected Future Policy Benefit, Original Discount Rate, before Cash Flow and Reinsurance, end of period		5,363.0		5,854.6
AOCI, Liability for Future Policy Benefit, Expected Future Policy Benefit, before Tax		(310.1)		(284.6)
Liability for Future Policy Benefit, Expected Future Policy Benefit, before Reinsurance, after Discount Rate Change, end of year		5,052.9		5,570.0
Liability for Future Policy Benefit, before Reinsurance, before Other		5,052.9		5,570.0
Liability for Future Policy Benefits, Other Contracts		0.5		0.5
Liability for Future Policy Benefit, before Reinsurance, after Other		5,053.4		5,570.5					7,295.7
Liability for Future Policy Benefit, Reinsurance Recoverable, after Allowance		32.8		36.8					58.3
Liability for Future Policy Benefit, after Reinsurance		5,020.6		5,533.7					7,237.4
Liability for Future Policy Benefit, Gross Premium Income		2,210.4		2,073.5
Liability for Future Policy Benefit, Expected Future Policy Benefit, Interest Expense		137.6		162.2
Liability for Future Policy Benefit, Expected Future Policy Benefit, Undiscounted, before Reinsurance		6,474.2		7,077.3
Liability for Future Policy Benefit, Expected Future Gross Premium, Undiscounted, before Reinsurance		0.0		0.0
Liability for Future Policy Benefit, Expected Future Gross Premium, Discounted, before Reinsurance		$ 0.0		$ 0.0
Liability for Future Policy Benefit, Weighted-Average Interest Accretion Rate		4.00%		3.80%
Liability for Future Policy Benefit, Current Weighted-Average Discount Rate		5.40%		5.00%
Liability for Future Policy Benefit, Weighted-Average Duration		4 years 3 months 18 days		4 years 4 months 24 days
Group Life and AD&D | Unum US
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Liability for Future Policy Benefit, Expected Net Premium, before Reinsurance, after Discount Rate Change, balance beginning of year		$ 0.0		$ 0.0
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Cash Flow and Reinsurance, balance at beginning of period		0.0		0.0
Liability for Future Policy Benefit, Expected Net Premium, Cumulative Increase (Decrease) from Cash Flow Change						0.0		0.0
Liability for Future Policy Benefit, Expected Net Premium, Cumulative Increase (Decrease) of Actual Variance from Expected Experience						0.0		0.0
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Reinsurance, after Cash Flow Change						0.0		0.0
Liability for Future Policy Benefit, Expected Net Premium, Issuance		0.0		0.0
Liability for Future Policy Benefit, Expected Net Premium, Interest Income		0.0		0.0
Liability for Future Policy Benefit, Expected Net Premium, Net Premium Collected		0.0		0.0
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Cash Flow and Reinsurance, balance at end of period		0.0		0.0
AOCI, Liability for Future Policy Benefit, Expected Net Premium, before Tax		0.0		0.0
Liability for Future Policy Benefit, Expected Net Premium, before Reinsurance, after Discount Rate Change		0.0		0.0
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Liability for Future Policy Benefit, Expected Future Policy Benefit, before Reinsurance, after Discount Rate Change, beginning of year		972.6		1,124.1
Liability for Future Policy Benefit, Expected Future Policy Benefit, Original Discount Rate, before Cash Flow and Reinsurance, beginning of period		998.5		1,058.3
Liability for Future Policy Benefit, Expected Future Policy Benefit, Cumulative Increase (Decrease) from Cash Flow Change						0.0		(32.9)
Liability for Future Policy Benefit, Expected Future Policy Benefit, Cumulative Increase (Decrease) of Actual Variance from Expected Experience						(28.2)		(29.0)
Liability for Future Policy Benefit, Expected Future Benefit, Original Discount Rate, before Reinsurance, after Cash Flow Change						970.3		996.4
Liability for Future Policy Benefit, Expected Future Policy Benefit, Issuance		356.1	[7]	377.5	[8]
Liability for Future Policy Benefit, Expected Future Policy Benefit, Interest Expense		15.8		18.8
Liability for Future Policy Benefit, Expected Future Policy Benefit, Benefit Payment		(402.1)		(424.1)
Liability for Future Policy Benefit, Expected Future Policy Benefit, Original Discount Rate, before Cash Flow and Reinsurance, end of period		940.1		968.6
AOCI, Liability for Future Policy Benefit, Expected Future Policy Benefit, before Tax		(35.6)		(32.5)
Liability for Future Policy Benefit, Expected Future Policy Benefit, before Reinsurance, after Discount Rate Change, end of year		904.5		936.1
Liability for Future Policy Benefit, before Reinsurance, before Other		904.5		936.1
Liability for Future Policy Benefits, Other Contracts		1.0		0.9
Liability for Future Policy Benefit, before Reinsurance, after Other		905.5		937.0					1,127.3
Liability for Future Policy Benefit, Reinsurance Recoverable, after Allowance		6.2		6.0					3.0
Liability for Future Policy Benefit, after Reinsurance		899.3		931.0					1,124.3
Liability for Future Policy Benefit, Gross Premium Income		1,403.2		1,396.0
Liability for Future Policy Benefit, Expected Future Policy Benefit, Interest Expense		15.8		18.8
Liability for Future Policy Benefit, Expected Future Policy Benefit, Undiscounted, before Reinsurance		1,069.2		1,124.5
Liability for Future Policy Benefit, Expected Future Gross Premium, Undiscounted, before Reinsurance		0.0		0.0
Liability for Future Policy Benefit, Expected Future Gross Premium, Discounted, before Reinsurance		$ 0.0		$ 0.0
Liability for Future Policy Benefit, Weighted-Average Interest Accretion Rate		2.30%		2.40%
Liability for Future Policy Benefit, Current Weighted-Average Discount Rate		3.10%		3.10%
Liability for Future Policy Benefit, Weighted-Average Duration		2 years 8 months 12 days		3 years 1 month 6 days
Individual Disability | Unum US
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Liability for Future Policy Benefit, Expected Net Premium, before Reinsurance, after Discount Rate Change, balance beginning of year		$ 1,202.9		$ 1,494.3
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Cash Flow and Reinsurance, balance at beginning of period		1,228.1		1,279.6
Liability for Future Policy Benefit, Expected Net Premium, Cumulative Increase (Decrease) from Cash Flow Change						5.0		(73.7)
Liability for Future Policy Benefit, Expected Net Premium, Cumulative Increase (Decrease) of Actual Variance from Expected Experience						(13.6)		(37.4)
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Reinsurance, after Cash Flow Change						1,219.5		1,168.5
Liability for Future Policy Benefit, Expected Net Premium, Issuance		164.0		123.5
Liability for Future Policy Benefit, Expected Net Premium, Interest Income		36.3		38.2
Liability for Future Policy Benefit, Expected Net Premium, Net Premium Collected		(131.7)		(130.5)
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Cash Flow and Reinsurance, balance at end of period		1,288.1		1,199.7
AOCI, Liability for Future Policy Benefit, Expected Net Premium, before Tax		(62.2)		(37.2)
Liability for Future Policy Benefit, Expected Net Premium, before Reinsurance, after Discount Rate Change		1,225.9		1,162.5
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Liability for Future Policy Benefit, Expected Future Policy Benefit, before Reinsurance, after Discount Rate Change, beginning of year		3,192.8		4,017.3
Liability for Future Policy Benefit, Expected Future Policy Benefit, Original Discount Rate, before Cash Flow and Reinsurance, beginning of period		3,244.5		3,253.3
Liability for Future Policy Benefit, Expected Future Policy Benefit, Cumulative Increase (Decrease) from Cash Flow Change						7.9		(53.4)
Liability for Future Policy Benefit, Expected Future Policy Benefit, Cumulative Increase (Decrease) of Actual Variance from Expected Experience						(42.3)		(43.1)
Liability for Future Policy Benefit, Expected Future Benefit, Original Discount Rate, before Reinsurance, after Cash Flow Change						3,210.1		3,156.8
Liability for Future Policy Benefit, Expected Future Policy Benefit, Issuance		173.8		131.1
Liability for Future Policy Benefit, Expected Future Policy Benefit, Interest Expense		123.2		116.9
Liability for Future Policy Benefit, Expected Future Policy Benefit, Benefit Payment		(203.5)		(192.8)
Liability for Future Policy Benefit, Expected Future Policy Benefit, Original Discount Rate, before Cash Flow and Reinsurance, end of period		3,303.6		3,212.0
AOCI, Liability for Future Policy Benefit, Expected Future Policy Benefit, before Tax		(190.0)		(95.7)
Liability for Future Policy Benefit, Expected Future Policy Benefit, before Reinsurance, after Discount Rate Change, end of year		3,113.6		3,116.3
Liability for Future Policy Benefit, before Reinsurance, before Other		1,887.7		1,953.8
Liability for Future Policy Benefits, Other Contracts		26.0		24.7
Liability for Future Policy Benefit, before Reinsurance, after Other		1,913.7		1,978.5					2,767.7
Liability for Future Policy Benefit, Reinsurance Recoverable, after Allowance		148.1		189.7					260.6
Liability for Future Policy Benefit, after Reinsurance		1,765.6		1,788.8					2,507.1
Liability for Future Policy Benefit, Gross Premium Income		474.2		446.9
Liability for Future Policy Benefit, Expected Future Policy Benefit, Interest Expense		86.9		78.7
Liability for Future Policy Benefit, Expected Future Policy Benefit, Undiscounted, before Reinsurance		5,292.7		5,112.5
Liability for Future Policy Benefit, Expected Future Gross Premium, Undiscounted, before Reinsurance		5,701.8		5,461.8
Liability for Future Policy Benefit, Expected Future Gross Premium, Discounted, before Reinsurance		$ 4,099.5		$ 3,916.2
Liability for Future Policy Benefit, Weighted-Average Interest Accretion Rate		5.10%		5.10%
Liability for Future Policy Benefit, Current Weighted-Average Discount Rate		5.70%		5.20%
Liability for Future Policy Benefit, Weighted-Average Duration		9 years 7 months 6 days		9 years 4 months 24 days
Voluntary Benefits | Unum US
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Liability for Future Policy Benefit, Expected Net Premium, before Reinsurance, after Discount Rate Change, balance beginning of year		$ 868.2		$ 1,124.8
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Cash Flow and Reinsurance, balance at beginning of period		937.9		1,032.3
Liability for Future Policy Benefit, Expected Net Premium, Cumulative Increase (Decrease) from Cash Flow Change						180.7		(23.4)
Liability for Future Policy Benefit, Expected Net Premium, Cumulative Increase (Decrease) of Actual Variance from Expected Experience						(98.2)		(79.7)
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Reinsurance, after Cash Flow Change						1,020.4		929.2
Liability for Future Policy Benefit, Expected Net Premium, Issuance		258.6		126.0
Liability for Future Policy Benefit, Expected Net Premium, Interest Income		21.4		22.3
Liability for Future Policy Benefit, Expected Net Premium, Net Premium Collected		(124.2)		(128.6)
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Cash Flow and Reinsurance, balance at end of period		1,176.2		948.9
AOCI, Liability for Future Policy Benefit, Expected Net Premium, before Tax		(119.4)		(79.4)
Liability for Future Policy Benefit, Expected Net Premium, before Reinsurance, after Discount Rate Change		1,056.8		869.5
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Liability for Future Policy Benefit, Expected Future Policy Benefit, before Reinsurance, after Discount Rate Change, beginning of year		1,999.5		2,697.3
Liability for Future Policy Benefit, Expected Future Policy Benefit, Original Discount Rate, before Cash Flow and Reinsurance, beginning of period		2,141.2		2,201.8
Liability for Future Policy Benefit, Expected Future Policy Benefit, Cumulative Increase (Decrease) from Cash Flow Change						170.1		(39.9)
Liability for Future Policy Benefit, Expected Future Policy Benefit, Cumulative Increase (Decrease) of Actual Variance from Expected Experience						(109.6)		(82.3)
Liability for Future Policy Benefit, Expected Future Benefit, Original Discount Rate, before Reinsurance, after Cash Flow Change						2,201.7		2,079.6
Liability for Future Policy Benefit, Expected Future Policy Benefit, Issuance		270.4		140.5
Liability for Future Policy Benefit, Expected Future Policy Benefit, Interest Expense		64.3		65.2
Liability for Future Policy Benefit, Expected Future Policy Benefit, Benefit Payment		(143.9)		(147.5)
Liability for Future Policy Benefit, Expected Future Policy Benefit, Original Discount Rate, before Cash Flow and Reinsurance, end of period		2,392.5		2,137.8
AOCI, Liability for Future Policy Benefit, Expected Future Policy Benefit, before Tax		(280.7)		(167.5)
Liability for Future Policy Benefit, Expected Future Policy Benefit, before Reinsurance, after Discount Rate Change, end of year		2,111.8		1,970.3
Liability for Future Policy Benefit, before Reinsurance, before Other		1,055.0		1,100.8
Liability for Future Policy Benefits, Other Contracts		2.4		15.1
Liability for Future Policy Benefit, before Reinsurance, after Other		1,057.4		1,115.9					1,659.2
Liability for Future Policy Benefit, Reinsurance Recoverable, after Allowance		13.2		23.4					35.7
Liability for Future Policy Benefit, after Reinsurance		1,044.2		1,092.5					1,623.5
Liability for Future Policy Benefit, Gross Premium Income		592.1		583.1
Liability for Future Policy Benefit, Expected Future Policy Benefit, Interest Expense		42.9		42.9
Liability for Future Policy Benefit, Expected Future Policy Benefit, Undiscounted, before Reinsurance		5,107.4		4,555.1
Liability for Future Policy Benefit, Expected Future Gross Premium, Undiscounted, before Reinsurance		5,317.5		4,006.6
Liability for Future Policy Benefit, Expected Future Gross Premium, Discounted, before Reinsurance		$ 3,663.8		$ 2,970.1
Liability for Future Policy Benefit, Weighted-Average Interest Accretion Rate		5.00%		5.10%
Liability for Future Policy Benefit, Current Weighted-Average Discount Rate		5.70%		5.30%
Liability for Future Policy Benefit, Weighted-Average Duration		18 years 2 months 12 days		18 years
Other Insurance Product Line | Closed Block
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Liability for Future Policy Benefit, Expected Net Premium, before Reinsurance, after Discount Rate Change, balance beginning of year		$ 0.0		$ 0.0
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Cash Flow and Reinsurance, balance at beginning of period		0.0		0.0
Liability for Future Policy Benefit, Expected Net Premium, Cumulative Increase (Decrease) from Cash Flow Change						0.0		0.0
Liability for Future Policy Benefit, Expected Net Premium, Cumulative Increase (Decrease) of Actual Variance from Expected Experience						0.0		0.0
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Reinsurance, after Cash Flow Change						0.0		0.0
Liability for Future Policy Benefit, Expected Net Premium, Interest Income		0.0		0.0
Liability for Future Policy Benefit, Expected Net Premium, Net Premium Collected		0.0		0.0
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Cash Flow and Reinsurance, balance at end of period		0.0		0.0
AOCI, Liability for Future Policy Benefit, Expected Net Premium, before Tax		0.0		0.0
Liability for Future Policy Benefit, Expected Net Premium, before Reinsurance, after Discount Rate Change		0.0		0.0
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Liability for Future Policy Benefit, Expected Future Policy Benefit, before Reinsurance, after Discount Rate Change, beginning of year		8,218.8		10,414.4
Liability for Future Policy Benefit, Expected Future Policy Benefit, Original Discount Rate, before Cash Flow and Reinsurance, beginning of period		8,630.7		8,949.4
Liability for Future Policy Benefit, Expected Future Policy Benefit, Cumulative Increase (Decrease) from Cash Flow Change						0.0		216.9
Liability for Future Policy Benefit, Expected Future Policy Benefit, Cumulative Increase (Decrease) of Actual Variance from Expected Experience						4.1		18.1
Liability for Future Policy Benefit, Expected Future Benefit, Original Discount Rate, before Reinsurance, after Cash Flow Change						8,634.8		9,184.4
Liability for Future Policy Benefit, Expected Future Policy Benefit, Issuance		101.2	[9]	123.9	[10]
Liability for Future Policy Benefit, Expected Future Policy Benefit, Interest Expense		270.0		281.4
Liability for Future Policy Benefit, Expected Future Policy Benefit, Benefit Payment		(776.0)		(832.6)
Liability for Future Policy Benefit, Expected Future Policy Benefit, Original Discount Rate, before Cash Flow and Reinsurance, end of period		8,230.0		8,757.1
AOCI, Liability for Future Policy Benefit, Expected Future Policy Benefit, before Tax		(687.0)		(521.2)
Liability for Future Policy Benefit, Expected Future Policy Benefit, before Reinsurance, after Discount Rate Change, end of year		7,543.0		8,235.9
Liability for Future Policy Benefit, before Reinsurance, before Other		7,543.0		8,235.9
Liability for Future Policy Benefits, Other Contracts		1,606.0	[11]	1,759.9	[12]
Liability for Future Policy Benefit, before Reinsurance, after Other		9,149.0		9,995.8					14,251.1
Liability for Future Policy Benefit, Reinsurance Recoverable, after Allowance		7,173.7		7,834.2					9,957.0
Liability for Future Policy Benefit, after Reinsurance		1,975.3		2,161.6					4,294.1
Liability for Future Policy Benefit, Gross Premium Income		169.3		192.6
Liability for Future Policy Benefit, Expected Future Policy Benefit, Interest Expense		270.0		281.4
Liability for Future Policy Benefit, Expected Future Policy Benefit, Undiscounted, before Reinsurance		12,109.6		12,950.4
Liability for Future Policy Benefit, Expected Future Gross Premium, Undiscounted, before Reinsurance		0.0		0.0
Liability for Future Policy Benefit, Expected Future Gross Premium, Discounted, before Reinsurance		$ 0.0		$ 0.0
Liability for Future Policy Benefit, Weighted-Average Interest Accretion Rate		4.60%		4.60%
Liability for Future Policy Benefit, Current Weighted-Average Discount Rate		5.70%		5.30%
Liability for Future Policy Benefit, Weighted-Average Duration		7 years 3 months 18 days		7 years 4 months 24 days
Long-term Care | Closed Block
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Liability for Future Policy Benefit, Expected Net Premium, before Reinsurance, after Discount Rate Change, balance beginning of year		$ 6,412.6		$ 8,404.7
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Cash Flow and Reinsurance, balance at beginning of period		6,236.1		6,457.3
Liability for Future Policy Benefit, Expected Net Premium, Cumulative Increase (Decrease) from Cash Flow Change						1,641.3		27.8
Liability for Future Policy Benefit, Expected Net Premium, Cumulative Increase (Decrease) of Actual Variance from Expected Experience						54.9		(34.8)
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Reinsurance, after Cash Flow Change						7,932.3		6,450.3
Liability for Future Policy Benefit, Expected Net Premium, Interest Income		271.9		263.6
Liability for Future Policy Benefit, Expected Net Premium, Net Premium Collected		(438.1)		(424.1)
Liability for Future Policy Benefit, Expected Net Premium, Original Discount Rate, before Cash Flow and Reinsurance, balance at end of period		7,766.1		6,289.8
AOCI, Liability for Future Policy Benefit, Expected Net Premium, before Tax		(141.1)		98.2
Liability for Future Policy Benefit, Expected Net Premium, before Reinsurance, after Discount Rate Change		7,625.0		6,388.0
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Liability for Future Policy Benefit, Expected Future Policy Benefit, before Reinsurance, after Discount Rate Change, beginning of year		21,199.9		30,089.6
Liability for Future Policy Benefit, Expected Future Policy Benefit, Original Discount Rate, before Cash Flow and Reinsurance, beginning of period		20,221.6		19,870.8
Liability for Future Policy Benefit, Expected Future Policy Benefit, Cumulative Increase (Decrease) from Cash Flow Change						2,009.4		24.9
Liability for Future Policy Benefit, Expected Future Policy Benefit, Cumulative Increase (Decrease) of Actual Variance from Expected Experience						106.7		(39.3)
Liability for Future Policy Benefit, Expected Future Benefit, Original Discount Rate, before Reinsurance, after Cash Flow Change						$ 22,337.7		$ 19,856.4
Liability for Future Policy Benefit, Expected Future Policy Benefit, Issuance		0.0		0.0
Liability for Future Policy Benefit, Expected Future Policy Benefit, Interest Expense		850.7		829.7
Liability for Future Policy Benefit, Expected Future Policy Benefit, Benefit Payment		(624.2)		(548.7)
Liability for Future Policy Benefit, Expected Future Policy Benefit, Original Discount Rate, before Cash Flow and Reinsurance, end of period		22,564.2		20,137.4
AOCI, Liability for Future Policy Benefit, Expected Future Policy Benefit, before Tax		(579.3)		629.6
Liability for Future Policy Benefit, Expected Future Policy Benefit, before Reinsurance, after Discount Rate Change, end of year		21,984.9		20,767.0
Liability for Future Policy Benefit, before Reinsurance, before Other		14,359.9		14,379.0
Liability for Future Policy Benefits, Other Contracts		12.8		22.8
Liability for Future Policy Benefit, before Reinsurance, after Other		14,372.7		14,401.8					22,740.9
Liability for Future Policy Benefit, Reinsurance Recoverable, after Allowance		4.6		5.3					44.4
Liability for Future Policy Benefit, after Reinsurance		14,368.1		14,396.5					$ 22,696.5
Liability for Future Policy Benefit, Gross Premium Income		521.2		523.0
Liability for Future Policy Benefit, Expected Future Policy Benefit, Interest Expense		578.8		566.1
Liability for Future Policy Benefit, Expected Future Policy Benefit, Undiscounted, before Reinsurance		61,672.0		52,756.7
Liability for Future Policy Benefit, Expected Future Gross Premium, Undiscounted, before Reinsurance		14,678.9		12,812.7
Liability for Future Policy Benefit, Expected Future Gross Premium, Discounted, before Reinsurance		$ 8,311.0		$ 7,408.0
Liability for Future Policy Benefit, Weighted-Average Interest Accretion Rate		5.60%		5.50%
Liability for Future Policy Benefit, Current Weighted-Average Discount Rate		5.80%		5.30%
Liability for Future Policy Benefit, Weighted-Average Duration		16 years 7 months 6 days		15 years 8 months 12 days
Liability for Future Policy Benefit, Adverse Development, Expense		$ (215.5)

[1] 2We previously reported policy and contract benefits and reserves for future policy and contract benefits liabilities in our consolidated balance sheet as of September 30, 2022 of $1,771.4 million and $42,108.7 million, respectively, resulting in total policyholder liabilities of $43,880.1 million. These balances were reclassified into new line items, future policy benefits and policyholders' account balances, which would have reported balances of $38,079.8 million and $5,800.3 million, respectively, as of September 30, 2022, resulting in total policyholder liabilities of $43,880.1 million under the historical accounting method.

[2] 1We previously reported policy and contract benefits and reserves for future policy and contract benefits liabilities in our consolidated balance sheet as of December 31, 2022 of $1,839.8 million and $42,330.2 million, respectively, resulting in total policyholder liabilities of $44,170.0 million. These balances were reclassified into new line items, future policy benefits and policyholders' account balances, which would have reported balances of $38,443.2 million and $5,726.8 million, respectively, as of December 31, 2022, resulting in total policyholder liabilities of $44,170.0 million under the historical accounting method.

[3] 1Issuances include new policy issuances for most product lines. For our Unum US group disability, Unum US group life and AD&D and Closed Block - All Other product lines and certain of our Unum International product lines, this line represents new claim incurrals.

[4] 5These amounts represent the portion of reinsurance recoverable related to the liability for future policy benefits. These amounts include the adjustments for the removal of shadow adjustments and for the effect of change in discount rate assumptions for the liability for future policy benefits ceded to third party reinsurers.

[5] 1Unum US excludes dental & vision and medical stop-loss product lines and Closed Block excludes our participating fund account, which represents policies issued by one of our subsidiaries prior to its 1986 conversion from a mutual stock life insurance company. The liabilities associated with these products are included within Other products.

[6] 1Issuances for Unum International primarily represents new claim incurrals.

[7] 1Issuances include new policy issuances for most product lines. Issuances for Unum US group disability and Unum US group life and AD&D represents new claim incurrals.

[8] 1Issuances include new policy issuances for most product lines. Issuances for Unum US group disability and Unum US group life and AD&D represents new claim incurrals.

[9] 1Issuances for Closed Block - All Other represents new claim incurrals.

[10] 1Issuances for Closed Block - All Other represents new claim incurrals.

[11] 2Other for Closed Block - All Other primarily includes our closed block group pension products and certain of our ceded closed block individual life products.

[12] 2Other for Closed Block - All Other primarily includes our closed block group pension products and certain of our ceded closed block individual life products.