Contingencies (Health Care Cost Recovery Litigation) (Details) - Health Care Cost Recovery Actions [Member]	1 Months Ended	3 Months Ended		9 Months Ended
	Nov. 30, 1998 USD ($) state	Sep. 30, 2017 USD ($) case	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($) case	Sep. 30, 2016 USD ($)	Oct. 24, 2016 case	Oct. 26, 2015 case
Loss Contingencies [Line Items]
Number of cases pending | case						1	1
Number of states with settled litigation | state	46
State Settlement Agreements annual payments	$ 9,400,000,000
State Settlement Agreements attorney fees annual cap	$ 500,000,000
Litigation settlement		$ 1,100,000,000	$ 1,200,000,000	$ 3,400,000,000	$ 3,600,000,000
Canada [Member] | Threatened Litigation [Member]
Loss Contingencies [Line Items]
Number of cases pending | case		10		10