Shareholders' Equity and Noncontrolling Interests, Stock Repurchase (Details) - USD ($) $ in Millions			1 Months Ended	3 Months Ended		9 Months Ended	14 Months Ended
	Apr. 24, 2018	Jan. 24, 2017	Oct. 24, 2018	Sep. 30, 2018	Mar. 31, 2018	Sep. 30, 2018	Mar. 31, 2018
2017 Stock Repurchase Program
Shareholders' Equity
Value of shares authorized to be repurchased		$ 1,000.0
Repurchase of stock program, period		2 years
Number of shares repurchased and retired					4,200,000		12,600,000
Payments for shares repurchased and retired (in dollars)					$ 382.0		$ 1,000.0
2018 Stock Repurchase Program
Shareholders' Equity
Value of shares authorized to be repurchased	$ 2,000.0
Repurchase of stock program, period	3 years
Number of shares repurchased and retired			0	400,000		3,500,000
Payments for shares repurchased and retired (in dollars)				$ 34.8		$ 298.2
Value of shares remaining that may be repurchased under the stock repurchase program			$ 1,701.8