Restructuring (Restructuring Expenses) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($) Employees Rate
2018 Kansas City Restructuring Plan
Restructuring Cost and Reserve
Restructuring and Related Cost, Expected Number of Positions Eliminated | Employees	800
Restructuring and Related Cost, Expected Number of Positions Added | Employees	450
2018 Adelaide Restructuring Plan
Restructuring Cost and Reserve
Restructuring and Related Cost, Expected Number of Positions Eliminated | Employees	90
Motorcycles
Restructuring Cost and Reserve
Restructuring and Related Cost, Expected Cost, Percentage Paid In Cash | Rate	70.00%
Motorcycles | 2018 Reorganization Plan
Restructuring Cost and Reserve
Restructuring and Related Cost, Number of Positions Eliminated | Employees	70
Restructuring and Related Cost, Incurred Cost	$ 3.9
Motorcycles | Temporary Inefficiencies | Cost of goods sold
Restructuring Cost and Reserve
Restructuring and Related Cost, Incurred Cost	12.9
Minimum | Motorcycles
Restructuring Cost and Reserve
Restructuring and Related Cost, Expected Cost	152.0
Decrease in Restructuring and Related Costs, Expected Cost	3.0
Minimum | Motorcycles | Restructuring Expense
Restructuring Cost and Reserve
Restructuring and Related Cost, Expected Cost	129.0
Minimum | Motorcycles | Temporary Inefficiencies
Restructuring Cost and Reserve
Restructuring and Related Cost, Expected Cost	23.0
Minimum | Motorcycles | Employee Severance
Restructuring Cost and Reserve
Restructuring and Related Cost, Expected Cost	40.0
Minimum | Motorcycles | Accelerated Depreciation
Restructuring Cost and Reserve
Restructuring and Related Cost, Expected Cost	51.0
Minimum | Motorcycles | Other Project Implementation Costs
Restructuring Cost and Reserve
Restructuring and Related Cost, Expected Cost	38.0
Maximum | Motorcycles
Restructuring Cost and Reserve
Restructuring and Related Cost, Expected Cost	162.0
Decrease in Restructuring and Related Costs, Expected Cost	23.0
Maximum | Motorcycles | Restructuring Expense
Restructuring Cost and Reserve
Restructuring and Related Cost, Expected Cost	134.0
Maximum | Motorcycles | Temporary Inefficiencies
Restructuring Cost and Reserve
Restructuring and Related Cost, Expected Cost	28.0
Maximum | Motorcycles | Employee Severance
Restructuring Cost and Reserve
Restructuring and Related Cost, Expected Cost	41.0
Maximum | Motorcycles | Accelerated Depreciation
Restructuring Cost and Reserve
Restructuring and Related Cost, Expected Cost	53.0
Maximum | Motorcycles | Other Project Implementation Costs
Restructuring Cost and Reserve
Restructuring and Related Cost, Expected Cost	$ 40.0