Policyholder Account Balance, Guaranteed Minimum Crediting (Details) - USD ($) $ in Millions	Sep. 30, 2026	Dec. 31, 2025	Sep. 30, 2025	Dec. 31, 2024
Operating Segments
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	$ 5,326.8		$ 5,490.2
Policyholder Account Balance, Guaranteed Minimum Credit Rating | Operating Segments
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	5,083.3		5,222.0
Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0001 to 0050 | Operating Segments
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	237.0		261.6
Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0051 to 0150 | Operating Segments
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	6.5		6.6
Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0151 and Greater | Operating Segments
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	0.0		0.0
Colonial Life
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	840.3	$ 845.2	844.4	$ 849.0
Colonial Life | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0400 and 0500
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	840.3		844.4
Colonial Life | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0400 and 0500 | Policyholder Account Balance, Guaranteed Minimum Credit Rating
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	833.7		838.1
Colonial Life | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0400 and 0500 | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0001 to 0050
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	6.6		6.3
Colonial Life | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0400 and 0500 | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0051 to 0150
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	0.0		0.0
Colonial Life | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0400 and 0500 | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0151 and Greater
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	0.0		0.0
Other Insurance Product Line | Closed Block
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	3,954.9	4,073.4	4,093.0	4,052.2
Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Credit Rating
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	3,919.7		4,038.8
Other Insurance Product Line | Closed Block | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0001 to 0050
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	28.7		47.6
Other Insurance Product Line | Closed Block | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0051 to 0150
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	6.5		6.6
Other Insurance Product Line | Closed Block | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0151 and Greater
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	0.0		0.0
Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0300 and 0599
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	1,352.7		1,485.3
Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0300 and 0599 | Policyholder Account Balance, Guaranteed Minimum Credit Rating
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	1,317.5		1,431.1
Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0300 and 0599 | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0001 to 0050
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	28.7		47.6
Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0300 and 0599 | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0051 to 0150
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	6.5		6.6
Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0300 and 0599 | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0151 and Greater
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	0.0		0.0
Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0600 and 0899
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	23.0		25.7
Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0600 and 0899 | Policyholder Account Balance, Guaranteed Minimum Credit Rating
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	23.0		25.7
Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0600 and 0899 | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0001 to 0050
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	0.0		0.0
Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0600 and 0899 | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0051 to 0150
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	0.0		0.0
Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0600 and 0899 | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0151 and Greater
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	0.0		0.0
Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0900 and 1199
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	2,448.3		2,367.7
Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0900 and 1199 | Policyholder Account Balance, Guaranteed Minimum Credit Rating
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	2,448.3		2,367.7
Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0900 and 1199 | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0001 to 0050
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	0.0		0.0
Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0900 and 1199 | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0051 to 0150
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	0.0		0.0
Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0900 and 1199 | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0151 and Greater
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	0.0		0.0
Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 1200 and 1500
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	130.9		214.3
Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 1200 and 1500 | Policyholder Account Balance, Guaranteed Minimum Credit Rating
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	130.9		214.3
Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 1200 and 1500 | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0001 to 0050
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	0.0		0.0
Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 1200 and 1500 | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0051 to 0150
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	0.0		0.0
Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 1200 and 1500 | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0151 and Greater
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	0.0		0.0
Voluntary Benefits | Unum US
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	531.6	$ 548.4	552.8	$ 568.8
Voluntary Benefits | Unum US | Policyholder Account Balance, Guaranteed Minimum Credit Rating
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	329.9		345.1
Voluntary Benefits | Unum US | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0001 to 0050
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	201.7		207.7
Voluntary Benefits | Unum US | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0051 to 0150
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	0.0		0.0
Voluntary Benefits | Unum US | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0151 and Greater
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	0.0		0.0
Voluntary Benefits | Unum US | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0300 to 0399
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	80.7		86.6
Voluntary Benefits | Unum US | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0300 to 0399 | Policyholder Account Balance, Guaranteed Minimum Credit Rating
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	80.7		86.6
Voluntary Benefits | Unum US | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0300 to 0399 | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0001 to 0050
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	0.0		0.0
Voluntary Benefits | Unum US | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0300 to 0399 | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0051 to 0150
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	0.0		0.0
Voluntary Benefits | Unum US | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0300 to 0399 | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0151 and Greater
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	0.0		0.0
Voluntary Benefits | Unum US | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0400 and 0499
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	423.6		436.8
Voluntary Benefits | Unum US | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0400 and 0499 | Policyholder Account Balance, Guaranteed Minimum Credit Rating
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	221.9		229.1
Voluntary Benefits | Unum US | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0400 and 0499 | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0001 to 0050
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	201.7		207.7
Voluntary Benefits | Unum US | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0400 and 0499 | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0051 to 0150
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	0.0		0.0
Voluntary Benefits | Unum US | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0400 and 0499 | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0151 and Greater
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	0.0		0.0
Voluntary Benefits | Unum US | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0500 and 0600
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	27.3		29.4
Voluntary Benefits | Unum US | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0500 and 0600 | Policyholder Account Balance, Guaranteed Minimum Credit Rating
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	27.3		29.4
Voluntary Benefits | Unum US | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0500 and 0600 | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0001 to 0050
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	0.0		0.0
Voluntary Benefits | Unum US | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0500 and 0600 | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0051 to 0150
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	0.0		0.0
Voluntary Benefits | Unum US | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0500 and 0600 | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0151 and Greater
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, before Reserves in excess of Account Balance, End of Period	$ 0.0		$ 0.0
Minimum | Colonial Life | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0400 and 0500
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, Guaranteed Minimum Credit Rating	4.00%		4.00%
Minimum | Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0300 and 0599
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, Guaranteed Minimum Credit Rating	3.00%		3.00%
Minimum | Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0600 and 0899
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, Guaranteed Minimum Credit Rating	6.00%		6.00%
Minimum | Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0900 and 1199
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, Guaranteed Minimum Credit Rating	9.00%		9.00%
Minimum | Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 1200 and 1500
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, Guaranteed Minimum Credit Rating	12.00%		12.00%
Minimum | Voluntary Benefits | Unum US | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0300 to 0399
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, Guaranteed Minimum Credit Rating	3.00%		3.00%
Minimum | Voluntary Benefits | Unum US | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0400 and 0499
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, Guaranteed Minimum Credit Rating	4.00%		4.00%
Minimum | Voluntary Benefits | Unum US | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0500 and 0600
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, Guaranteed Minimum Credit Rating	5.00%		5.00%
Maximum | Colonial Life | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0400 and 0500
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, Guaranteed Minimum Credit Rating	5.00%		5.00%
Maximum | Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0300 and 0599
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, Guaranteed Minimum Credit Rating	5.99%		5.99%
Maximum | Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0600 and 0899
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, Guaranteed Minimum Credit Rating	8.99%		8.99%
Maximum | Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0900 and 1199
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, Guaranteed Minimum Credit Rating	11.99%		11.99%
Maximum | Other Insurance Product Line | Closed Block | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 1200 and 1500
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, Guaranteed Minimum Credit Rating	15.00%		15.00%
Maximum | Voluntary Benefits | Unum US | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0300 to 0399
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, Guaranteed Minimum Credit Rating	3.99%		3.99%
Maximum | Voluntary Benefits | Unum US | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0400 and 0499
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, Guaranteed Minimum Credit Rating	4.99%		4.99%
Maximum | Voluntary Benefits | Unum US | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0500 and 0600
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items]
Policyholder Account Balance, Guaranteed Minimum Credit Rating	6.00%		6.00%