Goodwill and Other Intangible Assets (Schedule of Goodwill) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Goodwill [Roll Forward]
Goodwill Gross, Balance, beginning of period	$ 7,373
Accumulated impairment losses, Balance, beginning of period	(2,814)
Goodwill, Balance, beginning of period	4,559
Goodwill acquired as part of acquisitions during current year	3
Goodwill allocated to hospitals held for sale	(68)	$ (77)
Goodwill Gross, Balance, end of period	7,308
Accumulated impairment losses, Balance, end of period	(2,814)
Goodwill, Balance, end of period	$ 4,494