Commitments And Contingencies (Schedule Of Activity Related To Asbestos Claim) (Detail) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2017 USD ($) LegalMatter	Sep. 30, 2016	Sep. 30, 2017 USD ($) LegalMatter	Sep. 30, 2016	Dec. 31, 2015	Apr. 22, 2016 USD ($)	Jun. 16, 2014 USD ($)
Loss Contingencies [Line Items]
Airplane Operating Lease Period Years			7
Fair Value Of Residual Value Guarantee	$ 11.1		$ 11.1
Fair Value Of Residual Value Guarantee, Fair Value of Operating Lease Asset Threshold	$ 14.4		$ 14.4
Asbestos Commitments and Contingencies
Loss Contingencies [Line Items]
Beginning claims	31,980	38,664	36,052	41,090
New claims	667	611	2,169	2,239	2,826
Settlements	(278)	(187)	(906)	(728)	(924)
Dismissals	(294)	(2,638)	(5,240)	(6,151)	(6,940)
Ending claims	32,075	36,450	32,075	36,450	41,090
New York | Asbestos Commitments and Contingencies
Loss Contingencies [Line Items]
Ending claims | LegalMatter	18,200		18,200
Texas | Asbestos Commitments and Contingencies
Loss Contingencies [Line Items]
Ending claims | LegalMatter	700		700
Mississippi | Asbestos Commitments and Contingencies
Loss Contingencies [Line Items]
Ending claims | LegalMatter	1,500		1,500
OHIO | Asbestos Commitments and Contingencies
Loss Contingencies [Line Items]
Ending claims | LegalMatter	200		200
George Coulbourn [Member] | Asbestos Commitments and Contingencies
Loss Contingencies [Line Items]
Court Judgment						$ 6.8
Ivan Sweberg [Member] | Asbestos Commitments and Contingencies
Loss Contingencies [Line Items]
Court Judgment							$ 5.3
Court_Reduced_Verdict							10.0
Paid Judgment Pursuant to Appeal			$ 5.7
Selwyn Hackshaw [Member] | Asbestos Commitments and Contingencies
Loss Contingencies [Line Items]
Court Judgment							3.1
Court_Reduced_Verdict							$ 6.0