Contingencies (Health Care Cost Recovery Litigation) (Details)	1 Months Ended	3 Months Ended
	Nov. 30, 1998 USD ($) state	Mar. 31, 2017 USD ($) case	Mar. 31, 2016 USD ($)	Apr. 25, 2016 case	Apr. 20, 2015 case
Loss Contingencies [Line Items]
Litigation settlement, amount | $			$ 1,200,000,000
Health Care Cost Recovery Actions [Member]
Loss Contingencies [Line Items]
Number of cases pending				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, amount | $		$ 1,100,000,000
NEW YORK [Member] | Health Care Cost Recovery Actions, Medicare as Secondary Payer Case [Member]
Loss Contingencies [Line Items]
Number of claims dismissed		2
Florida [Member] | Health Care Cost Recovery Actions, Medicare as Secondary Payer Case [Member]
Loss Contingencies [Line Items]
Number of claims dismissed		2
Massachusetts [Member] | Health Care Cost Recovery Actions, Medicare as Secondary Payer Case [Member]
Loss Contingencies [Line Items]
Number of claims dismissed		1
Canada [Member] | Threatened Litigation [Member] | Health Care Cost Recovery Actions [Member]
Loss Contingencies [Line Items]
Number of cases pending		10