Fair Value Measurement - Quantitative Information about Partnership's Level III Inputs (Detail) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2015 USD ($) $ / shares	Dec. 31, 2014 USD ($) Multiplier $ / shares
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair value of liabilities	$ 17,175.7	$ 16,269.9
Level III
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair value of assets	20,601.3	21,783.6
Fair value of liabilities	17,172.0	16,266.7
Level III | Senior secured notes | Discounted Cash Flow with Consensus Pricing
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair value of liabilities	$ 15,915.5	$ 14,757.5
Valuation Technique(s) Liabilities	Discounted Cash Flow with Consensus Pricing	Discounted Cash Flow with Consensus Pricing
Level III | Senior secured notes | Discounted Cash Flow with Consensus Pricing | Minimum
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Indicative Quotes Range Percentage	38.00%	35.00%
Recovery Rates Range Percentage	55.00%	63.00%
Discount Rate Range Percentage	1.00%	1.00%
Default Rates Range Percentage	1.00%	1.00%
Level III | Senior secured notes | Discounted Cash Flow with Consensus Pricing | Maximum
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Indicative Quotes Range Percentage	102.00%	100.00%
Recovery Rates Range Percentage	80.00%	75.00%
Discount Rate Range Percentage	12.00%	11.00%
Default Rates Range Percentage	5.00%	3.00%
Level III | Senior secured notes | Discounted Cash Flow with Consensus Pricing | Weighted Average
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Indicative Quotes Range Percentage	98.00%	98.00%
Recovery Rates Range Percentage	63.00%	68.00%
Discount Rate Range Percentage	3.00%	3.00%
Default Rates Range Percentage	3.00%	2.00%
Level III | Subordinated notes and preferred shares | Discounted Cash Flow with Consensus Pricing
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair value of liabilities	$ 1,112.4	$ 1,278.8
Valuation Technique(s) Liabilities	Discounted Cash Flow with Consensus Pricing	Discounted Cash Flow with Consensus Pricing
Level III | Subordinated notes and preferred shares | Discounted Cash Flow with Consensus Pricing | Minimum
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Indicative Quotes Range Percentage	1.00%	1.00%
Recovery Rates Range Percentage	55.00%	63.00%
Discount Rate Range Percentage	9.00%	8.00%
Default Rates Range Percentage	1.00%	1.00%
Level III | Subordinated notes and preferred shares | Discounted Cash Flow with Consensus Pricing | Maximum
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Indicative Quotes Range Percentage	101.00%	132.00%
Recovery Rates Range Percentage	80.00%	75.00%
Discount Rate Range Percentage	16.00%	15.00%
Default Rates Range Percentage	5.00%	3.00%
Level III | Subordinated notes and preferred shares | Discounted Cash Flow with Consensus Pricing | Weighted Average
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Indicative Quotes Range Percentage	55.00%	63.00%
Recovery Rates Range Percentage	64.00%	68.00%
Discount Rate Range Percentage	12.00%	10.00%
Default Rates Range Percentage	3.00%	2.00%
Level III | Combination notes | Consensus Pricing
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair value of liabilities	$ 18.8	$ 15.9
Valuation Technique(s) Liabilities	Consensus Pricing	Consensus Pricing
Level III | Combination notes | Consensus Pricing | Minimum
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Indicative Quotes Range Percentage	88.00%	97.00%
Level III | Combination notes | Consensus Pricing | Maximum
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Indicative Quotes Range Percentage	96.00%	98.00%
Level III | Combination notes | Consensus Pricing | Weighted Average
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Indicative Quotes Range Percentage	94.00%	98.00%
Level III | Loans Payable of a consolidated real estate VIE | Discounted Cash Flow
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair value of liabilities	$ 75.4	$ 146.2
Valuation Technique(s) Liabilities	Discounted Cash Flow	Discounted Cash Flow
Level III | Loans Payable of a consolidated real estate VIE | Discounted Cash Flow | Minimum
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Discount to Expected Payment	10.00%	0.00%
Discount Rate Range Percentage	20.00%	23.00%
Level III | Loans Payable of a consolidated real estate VIE | Discounted Cash Flow | Maximum
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Discount to Expected Payment	52.00%	100.00%
Discount Rate Range Percentage	30.00%	33.00%
Level III | Loans Payable of a consolidated real estate VIE | Discounted Cash Flow | Weighted Average
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Discount to Expected Payment	35.00%	36.00%
Discount Rate Range Percentage	23.00%	26.00%
Level III | Derivative instruments of Consolidated Funds | Counterparty Pricing
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair value of liabilities	$ 29.1	$ 17.2
Valuation Technique(s) Liabilities	Counterparty Pricing	Counterparty Pricing
Level III | Derivative instruments of Consolidated Funds | Counterparty Pricing | Minimum
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Indicative Quotes Range Notional Amount	3.00%	2.00%
Level III | Derivative instruments of Consolidated Funds | Counterparty Pricing | Maximum
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Indicative Quotes Range Notional Amount	34.00%	22.00%
Level III | Derivative instruments of Consolidated Funds | Counterparty Pricing | Weighted Average
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Indicative Quotes Range Notional Amount	22.00%	11.00%
Level III | Contingent cash consideration | Discounted Cash Flow
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair value of liabilities	$ 20.8	$ 51.1
Valuation Technique(s) Liabilities	Discounted Cash Flow	Discounted Cash Flow
Level III | Contingent cash consideration | Discounted Cash Flow | Minimum
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Assumed Range Percentage of Total Potential Contingent Payments	0.00%	0.00%
Discount Rate Range Percentage	4.00%	5.00%
Level III | Contingent cash consideration | Discounted Cash Flow | Maximum
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Assumed Range Percentage of Total Potential Contingent Payments	100.00%	100.00%
Discount Rate Range Percentage	22.00%	18.00%
Level III | Contingent cash consideration | Discounted Cash Flow | Weighted Average
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Assumed Range Percentage of Total Potential Contingent Payments	8.00%	20.00%
Discount Rate Range Percentage	9.00%	13.00%
Level III | Equity securities | Comparable Multiple 1
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair value of assets	$ 556.0	$ 1,783.7
Valuation Technique(s) Assets	Comparable Multiple	Comparable Multiple
Level III | Equity securities | Comparable Multiple 1 | Minimum
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
LTM EBITDA Multiple Range	1	4.8
Level III | Equity securities | Comparable Multiple 1 | Maximum
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
LTM EBITDA Multiple Range	20.4	16.2
Level III | Equity securities | Comparable Multiple 1 | Weighted Average
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
LTM EBITDA Multiple Range	11.4	12.1
Level III | Equity securities | Comparable Multiple 2
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair value of assets		$ 168.7
Valuation Technique(s) Assets		Comparable Multiple
Level III | Equity securities | Comparable Multiple 2 | Minimum
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Forward Ebitda Multiple Range | Multiplier		8.4
Level III | Equity securities | Comparable Multiple 2 | Maximum
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Forward Ebitda Multiple Range | Multiplier		8.4
Level III | Equity securities | Comparable Multiple 2 | Weighted Average
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Forward Ebitda Multiple Range | Multiplier		8.4
Level III | Equity securities | Consensus Pricing
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair value of assets	$ 6.1	$ 16.1
Valuation Technique(s) Assets	Consensus Pricing	Consensus Pricing
Level III | Equity securities | Consensus Pricing | Minimum
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Indicative Quotes Per Share | $ / shares	$ 0	$ 0
Level III | Equity securities | Consensus Pricing | Maximum
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Indicative Quotes Per Share | $ / shares	647	246
Level III | Equity securities | Consensus Pricing | Weighted Average
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Indicative Quotes Per Share | $ / shares	$ 0	$ 0
Level III | Equity securities | Discounted Cash Flow
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair value of assets	$ 8.0
Valuation Technique(s) Assets	Discounted Cash Flow
Level III | Equity securities | Discounted Cash Flow | Minimum
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Discount Rate Range Percentage	10.00%
Level III | Equity securities | Discounted Cash Flow | Maximum
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Discount Rate Range Percentage	10.00%
Level III | Equity securities | Discounted Cash Flow | Weighted Average
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Discount Rate Range Percentage	10.00%
Level III | Equity securities | Other Valuation Technique
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair value of assets	$ 5.2
Valuation Technique(s) Assets	Other
Level III | Bonds | Consensus Pricing
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair value of assets	$ 1,180.9	$ 1,235.8
Valuation Technique(s) Assets	Consensus Pricing	Consensus Pricing
Level III | Bonds | Consensus Pricing | Minimum
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Indicative Quotes Range Percentage	30.00%	1.00%
Level III | Bonds | Consensus Pricing | Maximum
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Indicative Quotes Range Percentage	112.00%	115.00%
Level III | Bonds | Consensus Pricing | Weighted Average
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Indicative Quotes Range Percentage	97.00%	98.00%
Level III | Loans | Consensus Pricing
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair value of assets	$ 15,673.3	$ 14,873.4
Valuation Technique(s) Assets	Consensus Pricing	Consensus Pricing
Level III | Loans | Consensus Pricing | Minimum
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Indicative Quotes Range Percentage	28.00%	0.00%
Level III | Loans | Consensus Pricing | Maximum
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Indicative Quotes Range Percentage	102.00%	103.00%
Level III | Loans | Consensus Pricing | Weighted Average
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Indicative Quotes Range Percentage	96.00%	98.00%
Level III | Loans | Market Yield Analysis
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair value of assets	$ 13.4	$ 211.5
Valuation Technique(s) Assets	Market Yield Analysis	Market Yield Analysis
Level III | Loans | Market Yield Analysis | Minimum
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Discount Rate Range Percentage	5.00%
Market Yield Range Percentage		5.00%
Level III | Loans | Market Yield Analysis | Maximum
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Discount Rate Range Percentage	16.00%
Market Yield Range Percentage		17.00%
Level III | Loans | Market Yield Analysis | Weighted Average
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Discount Rate Range Percentage	10.00%
Market Yield Range Percentage		11.00%
Level III | Partnership and LLC interests | Discounted Cash Flow
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair value of assets	$ 59.6
Valuation Technique(s) Assets	Discounted Cash Flow
Level III | Partnership and LLC interests | Discounted Cash Flow | Minimum
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Discount Rate Range Percentage	8.00%
Exit Cap Rate Valuation Technique	5.00%
Level III | Partnership and LLC interests | Discounted Cash Flow | Maximum
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Discount Rate Range Percentage	10.00%
Exit Cap Rate Valuation Technique	6.00%
Level III | Partnership and LLC interests | Discounted Cash Flow | Weighted Average
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Discount Rate Range Percentage	9.00%
Exit Cap Rate Valuation Technique	5.00%
Level III | Partnership and LLC interests | NAV of Underlying Fund
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair value of assets	$ 3,083.7	$ 3,481.0
Valuation Technique(s) Assets	NAV of Underlying Fund(1)	NAV of Underlying Fund(1)
Level III | Other | Counterparty Pricing
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair value of assets	$ 5.0	$ 1.5
Valuation Technique(s) Assets	Counterparty Pricing	Counterparty Pricing
Level III | Other | Counterparty Pricing | Minimum
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Indicative Quotes Range Notional Amount	1.00%	0.00%
Level III | Other | Counterparty Pricing | Maximum
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Indicative Quotes Range Notional Amount	22.00%	6.00%
Level III | Other | Counterparty Pricing | Weighted Average
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Indicative Quotes Range Notional Amount	7.00%	3.00%
Level III | Investments of Consolidated Funds
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair value of assets	$ 20,591.2	$ 21,771.7
Level III | Trading securities | Comparable Multiple 1
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair value of assets	$ 1.4	$ 3.0
Valuation Technique(s) Assets	Comparable Multiple	Comparable Multiple
Level III | Trading securities | Comparable Multiple 1 | Minimum
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
LTM EBITDA Multiple Range	5.8	5.8
Level III | Trading securities | Comparable Multiple 1 | Maximum
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
LTM EBITDA Multiple Range	5.8	5.8
Level III | Trading securities | Comparable Multiple 1 | Weighted Average
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
LTM EBITDA Multiple Range	5.8	5.8
Level III | Trading securities | Discounted Cash Flow
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair value of assets		$ 0.3
Valuation Technique(s) Assets		Discounted Cash Flow
Level III | Trading securities | Discounted Cash Flow | Minimum
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Discount Rate Range Percentage		10.00%
Level III | Trading securities | Discounted Cash Flow | Maximum
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Discount Rate Range Percentage		10.00%
Level III | Trading securities | Discounted Cash Flow | Weighted Average
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Discount Rate Range Percentage		10.00%
Level III | Restricted securities of Consolidated Funds | Consensus Pricing
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair value of assets	$ 8.7	$ 8.6
Valuation Technique(s) Assets	Consensus Pricing	Consensus Pricing
Level III | Restricted securities of Consolidated Funds | Consensus Pricing | Minimum
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Indicative Quotes Range Notional Amount	88.00%	87.00%
Level III | Restricted securities of Consolidated Funds | Consensus Pricing | Maximum
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Indicative Quotes Range Notional Amount	88.00%	87.00%
Level III | Restricted securities of Consolidated Funds | Consensus Pricing | Weighted Average
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Indicative Quotes Range Notional Amount	88.00%	87.00%