Goodwill and Other Intangible Assets (Schedule of Goodwill) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Goodwill [Roll Forward]
Goodwill Gross, Balance, beginning of period	$ 7,373.0
Accumulated impairment losses, Balance, beginning of period	(2,814.0)
Goodwill, Balance, beginning of period	4,559.0
Goodwill acquired as part of acquisitions during current year	2.0
Goodwill allocated to hospitals held for sale	(8.0)	$ (25.0)
Goodwill Gross, Balance, end of period	7,367.0
Accumulated impairment losses, Balance, end of period	(2,814.0)
Goodwill, Balance, end of period	$ 4,553.0