Investments in Affiliated Companies (Summarized Financial Data-RRPF) (Details 6) $ in Millions		12 Months Ended
		Dec. 31, 2019 USD ($) AircraftEngines	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Schedule of Equity Method Investments [Line Items]
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment		$ 3,190.2	$ 3,013.2
Income Statement [Abstract]
Lease revenue		469.8	436.9	$ 350.7
Net income		161.4	120.5	100.4
Assets [Abstract]
Current assets		203.6	303.8
Other noncurrent assets		5,015.9	4,417.5
Total assets		5,219.5	4,721.3
Liabilities and Equity [Abstract]
Current liabilities		525.5	827.8
Long-term debt		3,703.6	3,001.8
Shareholders’ equity		990.4	891.7
Total liabilities and shareholders' equity		5,219.5	4,721.3
RRPF Joint Ventures [Member]
Schedule of Equity Method Investments [Line Items]
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment		$ 1,178.5	1,024.7
Number of Aircraft Engines | AircraftEngines		478
Income Statement [Abstract]
Depreciation expense		$ (223.9)	(195.6)	(176.4)
Interest expense		(126.4)	(94.3)	(64.3)
Other expenses		(16.5)	(12.6)	(8.9)
Gains on sales of assets		86.4	12.5	20.5
Income before income taxes		189.6	121.3	115.7
Income taxes	[1]	(27.9)	(18.1)	(13.2)
Net income		161.7	103.2	102.5
Assets [Abstract]
Current assets		202.6	301.9
Operating assets, net of accumulated depreciation of $744.5 and $651.8	[2]	5,015.9	4,417.5
Total assets		5,218.5	4,719.4
EquityMethodInvestmentSummarizedFinancialInformationAPandAccruedExpense		96.2	97.9
Liabilities and Equity [Abstract]
Current liabilities		429.3	729.3
Long-term debt		3,367.5	2,722.4
Other liabilities		336.1	279.4
Shareholders’ equity		989.4	890.4
Total liabilities and shareholders' equity		5,218.5	4,719.4
RRPF Joint Ventures [Member] | Third Parties [Member]
Income Statement [Abstract]
Lease revenue		213.3	178.6	168.8
RRPF Joint Ventures [Member] | Rolls Royce [Member]
Income Statement [Abstract]
Lease revenue		$ 256.7	$ 232.7	$ 176.0

[1]

[2] (a) All operating assets were pledged as collateral for long-term debt obligations.