Other Comprehensive Income (Schedule of Changes in Accumulated Other Comprehensive Income (Loss) by Component) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Beginning Balance	$ (62)	$ (73)
Other comprehensive income (loss) before reclassifications	13	(14)
Amounts reclassified from accumulated other comprehensive income	28	23
Other comprehensive income (loss)	41	9	$ (10)
AOCI distributed to QHC in spin-off		2
Accumulated Other Comprehensive Income (Loss), Ending Balance	(21)	(62)	(73)
Change in Fair Value of Interest Rate Swaps [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Beginning Balance	(31)	(48)
Other comprehensive income (loss) before reclassifications		(17)
Amounts reclassified from accumulated other comprehensive income	19	34
Other comprehensive income (loss)	19	17
Accumulated Other Comprehensive Income (Loss), Ending Balance	(12)	(31)	(48)
Change in Fair Value of Available for Sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Beginning Balance	(10)	1
Other comprehensive income (loss) before reclassifications	8	2
Amounts reclassified from accumulated other comprehensive income		(13)
Other comprehensive income (loss)	8	(11)
AOCI distributed to QHC in spin-off
Accumulated Other Comprehensive Income (Loss), Ending Balance	(2)	(10)	1
Change in Unrecognized Pension Cost Components [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Beginning Balance	(21)	(26)
Other comprehensive income (loss) before reclassifications	5	1
Amounts reclassified from accumulated other comprehensive income	9	2
Other comprehensive income (loss)	14	3
AOCI distributed to QHC in spin-off		2
Accumulated Other Comprehensive Income (Loss), Ending Balance	$ (7)	$ (21)	$ (26)