Contingencies (Federal Government's Lawsuit) (Details) - USD ($) $ in Millions	1 Months Ended		3 Months Ended
	Dec. 31, 2011	Aug. 31, 2006	Mar. 31, 2018	Mar. 31, 2017	Jun. 30, 2014
Loss Contingencies [Line Items]
Loss contingency, amount of district court deposit			$ 23.0	$ 1.0
Federal Governments Lawsuit [Member]
Loss Contingencies [Line Items]
Disclosure period		10 years
Federal Governments Lawsuit [Member] | PM USA [Member]
Loss Contingencies [Line Items]
Loss contingency, amount of district court deposit	$ 3.1
Loss contingency installment period, years	5 years
Implementation of Corrective Communications [Member] | Federal Governments Lawsuit [Member]
Loss Contingencies [Line Items]
Provision related to litigation recorded					$ 31.0