Goodwill and Other Intangible Assets (Schedule of Goodwill) (Details) - USD ($) $ in Millions	6 Months Ended	9 Months Ended	12 Months Ended
	Jun. 30, 2016	Sep. 30, 2016	Dec. 31, 2017	Dec. 31, 2016
Goodwill [Roll Forward]
Balance, beginning of year	$ 8,965	$ 8,965	$ 6,521	$ 8,965
Goodwill acquired as part of acquisitions during current year			5	71
Consideration and purchase price allocation adjustments for prior year's acquisitions and other adjustments			(27)
Goodwill allocated to QHC in the spin-off				(709)
Goodwill in the home care operations reporting unit included in the sale of a majority interest in the home care division				(46)
Goodwill allocated to hospitals held for sale			(357)	(365)
Impairment of goodwill	$ (1,400)	$ (1,395)	(1,419)	(1,395)
Balance, end of year			$ 4,723	$ 6,521