Contingencies (Engle Class Action And Engle Progeny Trial Results) (Details)		1 Months Ended			3 Months Ended		12 Months Ended	162 Months Ended
	Apr. 23, 2018 USD ($) case plantiff	Feb. 29, 2008 USD ($)	Jul. 31, 2006 USD ($) plantiff	May 31, 2001 USD ($)	Mar. 31, 2018 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2015 USD ($) case	Mar. 31, 2018 USD ($)	Jul. 31, 2000 USD ($)
Loss Contingencies [Line Items]
Payments made related to litigation | $					$ 23,000,000	$ 1,000,000
Engle Progeny Cases [Member]
Loss Contingencies [Line Items]
Punitive damages awarded | $									$ 145,000,000,000
Engle Progeny Cases [Member] | PM USA [Member]
Loss Contingencies [Line Items]
Punitive damages awarded | $									$ 74,000,000,000
Amounts placed in escrow | $				$ 500,000,000
Period for members of decertified class to file individual actions against defendants			1 year
Engle Progeny Cases [Member] | PM USA [Member] | Subsequent Event [Member]
Loss Contingencies [Line Items]
Number of verdicts returned	118
Number of unfavorable verdicts	63
Number of claims with unfavorable verdicts pending/reversed	8
Number of favorable verdicts	45
Number of verdicts reversed	2
Engle Progeny Cases, Federal [Member] | PM USA [Member]
Loss Contingencies [Line Items]
Amounts placed in escrow | $							$ 43,000,000	$ 43,000,000
Number of claims resolved							415
Engle Progeny Cases, Federal [Member] | PM USA [Member] | Subsequent Event [Member]
Loss Contingencies [Line Items]
Number of cases pending	11
Engle Progeny Cases, State [Member] | Subsequent Event [Member]
Loss Contingencies [Line Items]
Number of cases pending	2,300
Number of plaintiffs | plantiff	3,000
Engle Progeny Cases, State [Member] | PM USA [Member] | Subsequent Event [Member]
Loss Contingencies [Line Items]
Number of favorable verdicts	36
Engle Progeny Cases, D. Cohen and Collar [Member] | PM USA [Member] | Subsequent Event [Member]
Loss Contingencies [Line Items]
Number of verdicts reversed	2
Engle Progeny Cases, Reider and Banks [Member] | PM USA [Member] | Subsequent Event [Member]
Loss Contingencies [Line Items]
Damages awarded, value | $	$ 0
Engle Progeny Cases, Weingart and Hancock [Member] | PM USA [Member] | Subsequent Event [Member]
Loss Contingencies [Line Items]
Damages awarded, value | $	$ 0
Florida [Member] | Engle Progeny Cases, State [Member]
Loss Contingencies [Line Items]
Compensatory damages awarded | $			$ 6,900,000
Florida [Member] | Engle Progeny Cases, State [Member] | PM USA [Member]
Loss Contingencies [Line Items]
Number of individual plaintiffs reinstated | plantiff			2
Payments made related to litigation | $		$ 3,000,000