Additional Information - Merger with Kemper Corporation (Details) - Kemper Corporation $ / shares in Units, $ in Billions |
Feb. 13, 2018
USD ($)
$ / shares
shares
|
Feb. 12, 2018
USD ($)
employee
$ / shares
|
|---|---|---|
| Business Acquisition [Line Items] | ||
| Transaction value | $ | $ 1.4 | $ 1.3 |
| Weighted average share price (usd per share) | $ 64.40 | |
| Share price (usd per share) | 57.75 | |
| Business acquisition, share price (usd per share) | $ 129.00 | $ 121.01 |
| Entity Number of Employees | employee | 5,550 | |
| Cash, mixed consideration (use per share) | $ 51.60 | |
| Stock, mixed consideration (shares) | shares | 1.2019 | |
| Cash, cash consideration (usd per share) | $ 129.00 | |
| Stock, stock consideration (shares) | shares | 2.0031 | |
| Percentage of ownership | 20.00% |