Income Taxes (Details) - USD ($) $ in Millions			3 Months Ended		12 Months Ended
	Jan. 01, 2018	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Income Taxes
Corporate federal statutory tax rate			35.00%
Decrease in income tax expense due to change in enacted rate			$ 102
Foreign earnings deemed repatriated			1,048
Deferred tax liabilities, deemed repatriated earnings		$ 75	75
Tax expense on deemed repatriated earnings			$ 40
Effective income tax rate			(8.90%)	28.60%
Statute of limitations, minimum			3 years
Statute of limitations, maximum			5 years
Net income tax payments			$ 7	$ 63
Gross unrecognized tax benefits		214	214				$ 201
Unrecognized tax benefits that, if recognized, would impact the effective income tax rate		183	183				169
Accrued interest and penalties related to unrecognized tax benefits recognized within Other Liabilities		9	9				$ 8
Tax interest and penalties			0	$ 0
Minimum
Income Taxes
Anticipated reduction in the unrecognized tax benefits during the next 12 months		0	0
Maximum
Income Taxes
Anticipated reduction in the unrecognized tax benefits during the next 12 months		49	49
B/E Aerospace
Income Taxes
Foreign earnings deemed repatriated		250
Liability assumed, deferred tax liability from deemed repatriated earnings		$ 35	$ 35
Forecast
Income Taxes
Corporate federal statutory tax rate					21.00%
Blended federal statutory tax rate						24.60%
Subsequent Event
Income Taxes
Corporate federal statutory tax rate	21.00%