XML 101 R84.htm IDEA: XBRL DOCUMENT
v3.25.4

Policyholder Account Balance, Guaranteed Minimum Crediting (Detail) - USD ($) $ in Millions | Dec. 31, 2025 | Dec. 31, 2024 | Dec. 31, 2023 | Dec. 31, 2022
--- | --- | --- | --- | ---
Operating Segments |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items] |  |  |  |
Policyholder Account Balance, before Reserves in excess of Account Balance | $ 5,467.0 | $ 5,470.0 | $ 5,514.2 | $ 5,598.6
Colonial Life |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items] |  |  |  |
Policyholder Account Balance, before Reserves in excess of Account Balance | 845.2 | 849.0 | 852.9 | 852.4
Voluntary Benefits | Unum US |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items] |  |  |  |
Policyholder Account Balance, before Reserves in excess of Account Balance | 548.4 | 568.8 | 578.6 | 586.8
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 | 4,073.4 | 4,052.2 | 4,082.7 | $ 4,159.4
Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0300 to 0399 | Voluntary Benefits | Unum US |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items] |  |  |  |
Policyholder Account Balance, before Reserves in excess of Account Balance | $ 85.6 | $ 89.3 | $ 91.9 |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0300 to 0399 | Minimum | Voluntary Benefits | Unum US |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items] |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Credit Rating | 3.00% | 3.00% | 3.00% |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0300 to 0399 | Maximum | Voluntary Benefits | Unum US |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items] |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Credit Rating | 3.99% | 3.99% | 3.99% |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0400 and 0499 | Voluntary Benefits | Unum US |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items] |  |  |  |
Policyholder Account Balance, before Reserves in excess of Account Balance | $ 433.5 | $ 448.6 | $ 454.9 |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0400 and 0499 | Minimum | Voluntary Benefits | Unum US |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items] |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Credit Rating | 4.00% | 4.00% | 4.00% |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0400 and 0499 | Maximum | Voluntary Benefits | Unum US |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items] |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Credit Rating | 4.99% | 4.99% | 4.99% |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0500 and 0600 | Voluntary Benefits | Unum US |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items] |  |  |  |
Policyholder Account Balance, before Reserves in excess of Account Balance | $ 29.3 | $ 30.9 | $ 31.8 |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0500 and 0600 | Minimum | Voluntary Benefits | Unum US |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items] |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Credit Rating | 5.00% | 5.00% | 5.00% |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0500 and 0600 | Maximum | Voluntary Benefits | Unum US |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items] |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Credit Rating | 6.00% | 6.00% | 6.00% |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0400 and 0500 | Colonial Life |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items] |  |  |  |
Policyholder Account Balance, before Reserves in excess of Account Balance | $ 845.2 | $ 849.0 | $ 852.9 |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0400 and 0500 | Minimum | Colonial Life |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items] |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Credit Rating | 4.00% | 4.00% | 4.00% |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0400 and 0500 | Maximum | Colonial Life |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items] |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Credit Rating | 5.00% | 5.00% | 5.00% |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0300 and 0599 | 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 | $ 1,450.9 | $ 1,532.2 | $ 1,639.3 |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0300 and 0599 | Minimum | Other Insurance Product Line | Closed Block |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items] |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Credit Rating | 3.00% | 3.00% | 3.00% |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0300 and 0599 | Maximum | Other Insurance Product Line | Closed Block |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items] |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Credit Rating | 5.99% | 5.99% | 5.99% |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0600 and 0899 | 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 | $ 25.5 | $ 26.0 | $ 32.3 |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0600 and 0899 | Minimum | Other Insurance Product Line | Closed Block |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items] |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Credit Rating | 6.00% | 6.00% | 6.00% |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0600 and 0899 | Maximum | Other Insurance Product Line | Closed Block |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items] |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Credit Rating | 8.99% | 8.99% | 8.99% |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0900 and 1199 | 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 | $ 2,377.9 | $ 2,432.2 | $ 2,354.9 |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0900 and 1199 | Minimum | Other Insurance Product Line | Closed Block |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items] |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Credit Rating | 9.00% | 9.00% | 9.00% |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0900 and 1199 | Maximum | Other Insurance Product Line | Closed Block |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items] |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Credit Rating | 11.99% | 11.99% | 11.99% |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 1200 and 1500 | 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 | $ 219.1 | $ 61.8 | $ 56.2 |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 1200 and 1500 | Minimum | Other Insurance Product Line | Closed Block |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items] |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Credit Rating | 12.00% | 12.00% | 12.00% |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 1200 and 1500 | Maximum | Other Insurance Product Line | Closed Block |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items] |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Credit Rating | 15.00% | 15.00% | 15.00% |
Policyholder Account Balance, at Guaranteed Minimum Crediting Rate | Operating Segments |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items] |  |  |  |
Policyholder Account Balance, before Reserves in excess of Account Balance | $ 5,223.8 | $ 3,762.4 | $ 2,044.0 |
Policyholder Account Balance, at Guaranteed Minimum Crediting Rate | Voluntary Benefits | Unum US |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items] |  |  |  |
Policyholder Account Balance, before Reserves in excess of Account Balance | 347.1 | 338.7 | 350.8 |
Policyholder Account Balance, at Guaranteed Minimum Crediting Rate | 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 | 4,037.9 | 2,581.0 | 846.5 |
Policyholder Account Balance, at Guaranteed Minimum Crediting Rate | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0300 to 0399 | Voluntary Benefits | Unum US |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items] |  |  |  |
Policyholder Account Balance, before Reserves in excess of Account Balance | 85.6 | 89.3 | 91.9 |
Policyholder Account Balance, at Guaranteed Minimum Crediting Rate | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0400 and 0499 | Voluntary Benefits | Unum US |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items] |  |  |  |
Policyholder Account Balance, before Reserves in excess of Account Balance | 232.2 | 218.5 | 227.1 |
Policyholder Account Balance, at Guaranteed Minimum Crediting Rate | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0500 and 0600 | Voluntary Benefits | Unum US |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items] |  |  |  |
Policyholder Account Balance, before Reserves in excess of Account Balance | 29.3 | 30.9 | 31.8 |
Policyholder Account Balance, at Guaranteed Minimum Crediting Rate | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0400 and 0500 | Colonial Life |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items] |  |  |  |
Policyholder Account Balance, before Reserves in excess of Account Balance | 838.8 | 842.7 | 846.7 |
Policyholder Account Balance, at Guaranteed Minimum Crediting Rate | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0300 and 0599 | 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 | 1,415.4 | 1,280.2 | 526.8 |
Policyholder Account Balance, at Guaranteed Minimum Crediting Rate | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0600 and 0899 | 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 | 25.5 | 26.0 | 1.3 |
Policyholder Account Balance, at Guaranteed Minimum Crediting Rate | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0900 and 1199 | 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 | 2,377.9 | 1,274.8 | 318.4 |
Policyholder Account Balance, at Guaranteed Minimum Crediting Rate | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 1200 and 1500 | 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 | 219.1 | 0.0 | 0.0 |
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 | 236.7 | 1,647.1 | 3,401.8 |
Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0001 to 0050 | Voluntary Benefits | Unum US |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items] |  |  |  |
Policyholder Account Balance, before Reserves in excess of Account Balance | 201.3 | 195.0 | 190.1 |
Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0001 to 0050 | 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 | 29.0 | 1,445.8 | 3,205.5 |
Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0001 to 0050 | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0300 to 0399 | Voluntary Benefits | Unum US |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items] |  |  |  |
Policyholder Account Balance, before Reserves in excess of Account Balance | 0.0 | 0.0 | 0.0 |
Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0001 to 0050 | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0400 and 0499 | Voluntary Benefits | Unum US |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items] |  |  |  |
Policyholder Account Balance, before Reserves in excess of Account Balance | 201.3 | 195.0 | 190.1 |
Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0001 to 0050 | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0500 and 0600 | Voluntary Benefits | Unum US |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items] |  |  |  |
Policyholder Account Balance, before Reserves in excess of Account Balance | 0.0 | 0.0 | 0.0 |
Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0001 to 0050 | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0400 and 0500 | Colonial Life |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items] |  |  |  |
Policyholder Account Balance, before Reserves in excess of Account Balance | 6.4 | 6.3 | 6.2 |
Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0001 to 0050 | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0300 and 0599 | 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 | 29.0 | 226.6 | 1,081.8 |
Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0001 to 0050 | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0600 and 0899 | 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 | 0.0 | 0.0 | 31.0 |
Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0001 to 0050 | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0900 and 1199 | 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 | 0.0 | 1,157.4 | 2,036.5 |
Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0001 to 0050 | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 1200 and 1500 | 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 | 0.0 | 61.8 | 56.2 |
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 | 6.5 | 60.5 | 68.4 |
Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0051 to 0150 | Voluntary Benefits | Unum US |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items] |  |  |  |
Policyholder Account Balance, before Reserves in excess of Account Balance | 0.0 | 35.1 | 37.7 |
Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0051 to 0150 | 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 | 6.5 | 25.4 | 30.7 |
Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0051 to 0150 | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0300 to 0399 | Voluntary Benefits | Unum US |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items] |  |  |  |
Policyholder Account Balance, before Reserves in excess of Account Balance | 0.0 | 0.0 | 0.0 |
Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0051 to 0150 | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0400 and 0499 | Voluntary Benefits | Unum US |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items] |  |  |  |
Policyholder Account Balance, before Reserves in excess of Account Balance | 0.0 | 35.1 | 37.7 |
Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0051 to 0150 | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0500 and 0600 | Voluntary Benefits | Unum US |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items] |  |  |  |
Policyholder Account Balance, before Reserves in excess of Account Balance | 0.0 | 0.0 | 0.0 |
Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0051 to 0150 | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0400 and 0500 | Colonial Life |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items] |  |  |  |
Policyholder Account Balance, before Reserves in excess of Account Balance | 0.0 | 0.0 | 0.0 |
Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0051 to 0150 | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0300 and 0599 | 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 | 6.5 | 25.4 | 30.7 |
Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0051 to 0150 | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0600 and 0899 | 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 | 0.0 | 0.0 | 0.0 |
Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0051 to 0150 | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0900 and 1199 | 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 | 0.0 | 0.0 | 0.0 |
Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0051 to 0150 | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 1200 and 1500 | 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 | 0.0 | 0.0 | 0.0 |
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 | 0.0 | 0.0 | 0.0 |
Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0151 and Greater | Voluntary Benefits | Unum US |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items] |  |  |  |
Policyholder Account Balance, before Reserves in excess of Account Balance | 0.0 | 0.0 | 0.0 |
Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0151 and Greater | 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 | 0.0 | 0.0 | 0.0 |
Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0151 and Greater | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0300 to 0399 | Voluntary Benefits | Unum US |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items] |  |  |  |
Policyholder Account Balance, before Reserves in excess of Account Balance | 0.0 | 0.0 | 0.0 |
Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0151 and Greater | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0400 and 0499 | Voluntary Benefits | Unum US |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items] |  |  |  |
Policyholder Account Balance, before Reserves in excess of Account Balance | 0.0 | 0.0 | 0.0 |
Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0151 and Greater | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0500 and 0600 | Voluntary Benefits | Unum US |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items] |  |  |  |
Policyholder Account Balance, before Reserves in excess of Account Balance | 0.0 | 0.0 | 0.0 |
Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0151 and Greater | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0400 and 0500 | Colonial Life |  |  |  |
Policyholder Account Balance, Guaranteed Minimum Crediting Rate [Line Items] |  |  |  |
Policyholder Account Balance, before Reserves in excess of Account Balance | 0.0 | 0.0 | 0.0 |
Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0151 and Greater | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0300 and 0599 | 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 | 0.0 | 0.0 | 0.0 |
Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0151 and Greater | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0600 and 0899 | 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 | 0.0 | 0.0 | 0.0 |
Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0151 and Greater | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0900 and 1199 | 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 | 0.0 | 0.0 | 0.0 |
Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0151 and Greater | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 1200 and 1500 | 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 | $ 0.0 | $ 0.0 | $ 0.0 |

X
- Definition Policyholder Account Balance, before Reserves in excess of Account Balance + References No definition available. + Details
Name: | unm_PolicyholderAccountBalanceBeforeReservesInExcessOfAccountBalance
Namespace Prefix: | unm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Guaranteed minimum crediting rate on policyholder account balance. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 55 -Paragraph 29F -Publisher FASB -URI https://asc.fasb.org/1943274/2147480046/944-40-55-29F Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 7A -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-7A + Details
Name: | us-gaap_PolicyholderAccountBalanceGuaranteedMinimumCreditRating
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 55 -Paragraph 29F -Publisher FASB -URI https://asc.fasb.org/1943274/2147480046/944-40-55-29F Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 7A -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-7A + Details
Name: | us-gaap_PolicyholderAccountBalanceGuaranteedMinimumCreditingRateLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | srt_ConsolidationItemsAxis=us-gaap_OperatingSegmentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=unm_ColonialLifeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=unm_VoluntaryBenefitsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=unm_UnumUsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=us-gaap_OtherInsuranceProductLineMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=unm_ClosedBlockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PolicyholderAccountBalanceGuaranteedMinimumCreditingRateRangeAxis=us-gaap_PolicyholderAccountBalanceGuaranteedMinimumCreditingRateRangeFrom0300To0399Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PolicyholderAccountBalanceGuaranteedMinimumCreditingRateRangeAxis=unm_PolicyholderAccountBalanceGuaranteedMinimumCreditingRateRangeFrom0400And0499Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PolicyholderAccountBalanceGuaranteedMinimumCreditingRateRangeAxis=unm_PolicyholderAccountBalanceGuaranteedMinimumCreditingRateRangeFrom0500And0600Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PolicyholderAccountBalanceGuaranteedMinimumCreditingRateRangeAxis=unm_PolicyholderAccountBalanceGuaranteedMinimumCreditingRateRangeFrom0400And0500Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PolicyholderAccountBalanceGuaranteedMinimumCreditingRateRangeAxis=unm_PolicyholderAccountBalanceGuaranteedMinimumCreditingRateRangeFrom0300And0599Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PolicyholderAccountBalanceGuaranteedMinimumCreditingRateRangeAxis=unm_PolicyholderAccountBalanceGuaranteedMinimumCreditingRateRangeFrom0600And0899Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PolicyholderAccountBalanceGuaranteedMinimumCreditingRateRangeAxis=unm_PolicyholderAccountBalanceGuaranteedMinimumCreditingRateRangeFrom0900And1199Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PolicyholderAccountBalanceGuaranteedMinimumCreditingRateRangeAxis=unm_PolicyholderAccountBalanceGuaranteedMinimumCreditingRateRangeFrom1200And1500Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PolicyholderAccountBalanceAboveGuaranteedMinimumCreditingRateAxis=us-gaap_PolicyholderAccountBalanceAtGuaranteedMinimumCreditingRateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PolicyholderAccountBalanceAboveGuaranteedMinimumCreditingRateAxis=us-gaap_PolicyholderAccountBalanceAboveGuaranteedMinimumCreditingRateRangeFrom0001To0050Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PolicyholderAccountBalanceAboveGuaranteedMinimumCreditingRateAxis=us-gaap_PolicyholderAccountBalanceAboveGuaranteedMinimumCreditingRateRangeFrom0051To0150Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PolicyholderAccountBalanceAboveGuaranteedMinimumCreditingRateAxis=us-gaap_PolicyholderAccountBalanceAboveGuaranteedMinimumCreditingRateRangeFrom0151AndGreaterMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |