Schedule I - Condensed Financial Information of the Registrant - Condensed Balance Sheets (Parenthetical) (Details) - USD ($) $ / shares in Units, $ in Millions	Dec. 31, 2022	Dec. 31, 2021
CONDENSED BALANCE SHEETS
Accumulated depreciation	$ 512.8	$ 650.4
Preferred stock, par value (USD per share)	$ 1.00	$ 1.00
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Common stock, par value (USD per share)	$ 0.01	$ 0.01
Common stock, shares authorized	2,000,000,000	2,000,000,000
Common stock, shares issued	373,500,000	393,800,000
Common stock, shares outstanding	373,500,000	393,800,000
Parent Company | Reportable Legal Entities
CONDENSED BALANCE SHEETS
Accumulated depreciation	$ 59.5	$ 50.1
Preferred stock, par value (USD per share)	$ 1.00	$ 1.00
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Common stock, par value (USD per share)	$ 0.01	$ 0.01
Common stock, shares authorized	2,000,000,000	2,000,000,000
Common stock, shares issued	373,500,000	393,800,000
Common stock, shares outstanding	373,500,000	393,800,000