GUARANTEES (Details) $ in Millions	Mar. 31, 2019 USD ($)
Guarantees
Total guarantees	$ 130.1
Guarantees expiring in less than 1 year	21.7
Guarantees expiring within 1 to 3 years	2.3
Guarantees with expiration over 3 years	106.1
Guarantees supporting commodity transactions of subsidiaries
Guarantees
Total guarantees	7.1
Guarantees expiring in less than 1 year	7.1
Guarantees expiring within 1 to 3 years	0.0
Guarantees with expiration over 3 years	0.0
Standby letters of credit
Guarantees
Total guarantees	102.8
Guarantees expiring in less than 1 year	5.7
Guarantees expiring within 1 to 3 years	1.1
Guarantees with expiration over 3 years	96.0
Surety bonds
Guarantees
Total guarantees	9.2
Guarantees expiring in less than 1 year	8.9
Guarantees expiring within 1 to 3 years	0.3
Guarantees with expiration over 3 years	0.0
Other guarantees
Guarantees
Total guarantees	11.0
Guarantees expiring in less than 1 year	0.0
Guarantees expiring within 1 to 3 years	0.9
Guarantees with expiration over 3 years	10.1
Other indemnifications
Guarantees
Total guarantees	11.0
Liability related to workers compensation coverage	10.1
Bluewater | Guarantees supporting commodity transactions of subsidiaries
Guarantees
Total guarantees	5.6
UMERC | Guarantees supporting commodity transactions of subsidiaries
Guarantees
Total guarantees	$ 1.5