Equity - Stock Repurchase Activities (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Accelerated Share Repurchases [Line Items]
Common stock received, aggregate price	$ 111.2	$ 2.1	$ 243.1	$ 245.3
Stock Repurchase Program 2018
Accelerated Share Repurchases [Line Items]
Stock repurchased (in shares)			9.3
Common stock received, aggregate price	110.0	$ 0.0	$ 235.0	$ 200.0
Common stock repurchased, average cost per share (in dollars per share)			$ 25.30
Stock repurchase program, remaining authorized repurchase amount	$ 1,100.0		$ 1,100.0