OTHER ASSETS, NET (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Intangible Assets
Less accumulated depreciation and amortization	$ (68.8)		$ (68.8)		$ (63.5)
Data processing software, net	39.0		39.0		37.5
Other assets	64.4		64.4		38.8
Other assets, net	103.4		103.4		76.3
Notes receivable, net	56.4		56.4		32.6
Amortization	31.8	$ 30.9	95.3	$ 93.5
Software development work in progress
Intangible Assets
Software	10.2		10.2		8.4
Data processing software
Intangible Assets
Software	97.6		97.6		$ 92.6
Amortization	$ 1.8	$ 1.7	$ 5.3	$ 5.2

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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