Intangible Assets (Tables)

3 Months Ended

Mar. 31, 2020

Intangible Assets, Net (Excluding Goodwill) [Abstract]

Schedule of Finite-Lived Intangible Assets by Major Class

The following table presents the major classes of the company's intangible assets at March 31, 2020 and December 31, 2019:

$ in millions	Gross Book Value	Accumulated Amortization		Net Book Value
March 31, 2020
Management contracts - indefinite-lived	6,962.0	N/A		6,962.0
Management contracts - finite-lived	319.2	(92.7	)	226.5
Developed technology	92.5	(35.0	)	57.5
Other	106.1	(27.0	)	79.1
Total	7,479.8	(154.7	)	7,325.1
December 31, 2019
Management contracts - indefinite-lived	6,969.1	N/A		6,969.1
Management contracts - finite-lived	319.3	(84.5	)	234.8
Developed technology	98.6	(31.7	)	66.9
Other	112.2	(24.7	)	87.5
Total	7,499.2	(140.9	)	7,358.3

Schedule of Future Amortization Expense Of Intangible Assets

Estimated amortization expense for each of the five succeeding fiscal years based upon the company's intangible assets at March 31, 2020 is as follows:

$ in millions Years Ended December 31,	Estimated Amortization Expense
2020 (excluding the three months ended March 31, 2020)	(46.2	)
2021	(62.5	)
2022	(59.5	)
2023	(52.0	)
2024	(46.8	)
2025	(38.9	)