Guarantees (Details 2)	Mar. 31, 2021 USD ($)
Guarantor Obligations [Line Items]
Guarantor obligations, maximum exposure, undiscounted	$ 235,800,000
Fixed maximum amounts guaranteed by year 2021	120,800,000
Fixed maximum amounts guaranteed by year 2022	42,400,000
Fixed maximum amounts guaranteed by year 2023	61,900,000
Fixed maximum amounts guaranteed by year 2024	500,000
Fixed maximum amounts guaranteed by year 2025	500,000
Fixed maximum amounts guaranteed, thereafter	700,000
No scheduled maturity date	9,000,000.0
Amount outstanding under guarantees that is reflected on balance sheet	0
Letters of credit	25,500,000
Letters of credit set to expire - 2021	23,600,000
Letters of credit set to expire - 2022	1,900,000
Outstanding letters of credit	0
Amount of surety bonds outstanding	$ 1,100,000,000