Guarantees (Details 2)	Mar. 31, 2020 USD ($)
Guarantor Obligations [Line Items]
Guarantor obligations, maximum exposure, undiscounted	$ 292,000,000.0
Fixed maximum amounts guaranteed by year 2020	129,200,000
Fixed maximum amounts guaranteed by year 2021	151,300,000
Fixed maximum amounts guaranteed by year 2022	400,000
Fixed maximum amounts guaranteed by year 2023	500,000
Fixed maximum amounts guaranteed by year 2024	500,000
Fixed maximum amounts guaranteed, thereafter	1,100,000
No scheduled maturity date	9,000,000.0
Amount outstanding under guarantees that is reflected on balance sheet	0
Letters of credit	26,800,000
Letters of credit set to expire - 2020	25,000,000.0
Letters of credit set to expire - 2021	1,800,000
Outstanding letters of credit	0
Amount of surety bonds outstanding	$ 1,200,000,000