Fair Value of Financial Instruments - Schedule of Unobservable Inputs Used for Level Three Fair Value Measurements of Financial Instruments on Recurring Basis (Detail) - USD ($) $ in Millions | 12 Months Ended | |
Sep. 30, 2016 | Sep. 30, 2015 | Sep. 30, 2014 | Sep. 30, 2013 |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | | | | | | | |
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value | | $ 763 | | $ 771.5 | | $ 302.1 | $ 471.3 |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings | | 48.4 | | 15.8 | | 30 | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Other Comprehensive Income (Loss) | | 0 | | | | | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases | | 0 | | 444.2 | | 150.6 | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Sales | | 0 | | 0 | | 0 | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements | | 56.9 | | (9.4) | | 349.8 | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Transfers, Net | | 0 | [1] | 0 | [2] | 0 | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings | | (1.4) | | (10.5) | | 3.3 | |
Funds Withheld Receivable | | 1,650.4 | | 1,710.1 | | | |
Assets, Fair Value Disclosure | | 78.1 | | 91.6 | | | |
Liabilities | | | | | | | |
Liabilities, Fair Value Disclosure | | 763 | | 771.5 | | | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss) | | | | | | 0 | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases | | 36.2 | | 30.4 | | 41.3 | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales | | 48 | | 14.1 | | 0.7 | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements | | 5.5 | | 50 | | 13.5 | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net | | 5.2 | [1] | 19.1 | [2] | 0 | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value | | 78.1 | | 91.6 | | 116.7 | 86.3 |
Funds Withheld Receivables [Member] | | | | | | | |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | | | | | | | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings | | | | (0.5) | | 1.5 | |
Liabilities | | | | | | | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases | | | | 30.4 | | 23.5 | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales | | | | 14.1 | | 0.7 | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value | | | | 74.7 | | 58.9 | 34.6 |
Funds withheld for reinsurance liability [Member] | | | | | | | |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | | | | | | | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings | | (3.6) | | | | | |
Liabilities | | | | | | | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss) | | 0 | | | | | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases | | 36.2 | | | | | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales | | 34.4 | | | | | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements | | 0 | | | | | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net | [1] | 5.2 | | | | | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value | | 78.1 | | 74.7 | | | |
Corporate Debt Securities [Member] | | | | | | | |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | | | | | | | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings | | (0.5) | | (2.2) | | 0 | |
Liabilities | | | | | | | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss) | | | | | | 0 | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases | | 0 | | | | 16.3 | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales | | 13.6 | | | | 0 | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements | | 0 | | | | 0 | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net | | | | | | 0 | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value | | | | 14.1 | | 16.3 | 0 |
Other invested assets | | | | | | | |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | | | | | | | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings | | 2.7 | | (16.3) | | | |
Liabilities | | | | | | | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss) | | 0 | | 0 | | | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases | | 0 | | 0 | | | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales | | 0 | | 0 | | | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements | | 5.5 | | 0 | | | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net | | 0 | [1] | 19.1 | [2] | | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value | | 0 | | 2.8 | | 0 | |
Fair Value, Measurements, Recurring | | | | | | | |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | | | | | | | |
Funds Withheld Receivable | | 1,535.1 | | 1,638.1 | | | |
Fair Value, Measurements, Recurring | Corporate Debt Securities [Member] | | | | | | | |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | | | | | | | |
Available-for-sale Securities | | $ 0 | | 14.1 | | | |
Contingent Purchase Price Reduction Receivable [Member] | | | | | | | |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | | | | | | | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings | | | | 8.5 | | 0.5 | |
Liabilities | | | | | | | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss) | | | | | | 0 | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases | | | | | | 0 | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales | | | | | | 0 | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements | | | | $ 50 | | 0 | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net | | | | | | 0 | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value | | | | | | 41.5 | $ 41 |
Minimum [Member] | FIA embedded derivatives, included in contractholder funds | | | | | | | |
Liabilities | | | | | | | |
Market value of option | | 0.00% | | 0.00% | | | |
Maximum | FIA embedded derivatives, included in contractholder funds | | | | | | | |
Liabilities | | | | | | | |
Market value of option | | 27.00% | | 32.00% | | | |
Weighted average | Other invested assets | | | | | | | |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | | | | | | | |
Probability of collection | | 0.00% | | 50.00% | | | |
Fair Value Inputs, Discount Rate | | 0.00% | | 10.00% | | | |
Weighted average | FIA embedded derivatives, included in contractholder funds | | | | | | | |
Liabilities | | | | | | | |
Market value of option | | 2.00% | | 1.00% | | | |
SWAP rates | | 1.00% | | 2.00% | | | |
Mortality multiplier | | 80.00% | | 80.00% | | | |
Non-performance spread | | 0.25% | | 0.25% | | | |
Broker Quoted [Member] | Funds withheld for reinsurance liability [Member] | | | | | | | |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | | | | | | | |
Valuation Technique | | Broker-quoted | | | | | |
Broker Quoted [Member] | Corporate Debt Securities [Member] | | | | | | | |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | | | | | | | |
Valuation Technique | | Broker-quoted | | | | | |
Broker Quoted [Member] | Minimum [Member] | Corporate Debt Securities [Member] | | | | | | | |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | | | | | | | |
Offered quotes | | 0.00% | | 0.00% | | | |
Broker Quoted [Member] | Minimum [Member] | Funds withheld for reinsurance liability [Member] | | | | | | | |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | | | | | | | |
Fair Value Inputs, Discount Rate | | 97.00% | | 99.00% | | | |
Broker Quoted [Member] | Maximum | Corporate Debt Securities [Member] | | | | | | | |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | | | | | | | |
Offered quotes | | 0.00% | | 0.00% | | | |
Broker Quoted [Member] | Maximum | Funds withheld for reinsurance liability [Member] | | | | | | | |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | | | | | | | |
Fair Value Inputs, Discount Rate | | 100.00% | | 103.00% | | | |
Broker Quoted [Member] | Weighted average | Corporate Debt Securities [Member] | | | | | | | |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | | | | | | | |
Offered quotes | | 0.00% | | 83.00% | | | |
Broker Quoted [Member] | Weighted average | Funds withheld for reinsurance liability [Member] | | | | | | | |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | | | | | | | |
Fair Value Inputs, Discount Rate | | 100.00% | | 101.00% | | | |
Discounted Cash Flow [Member] | Funds withheld for reinsurance liability [Member] | | | | | | | |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | | | | | | | |
Valuation Technique | | Loan Recovery Value | | | | | |
Discounted Cash Flow [Member] | Other invested assets | | | | | | | |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | | | | | | | |
Valuation Technique | | Discounted Cash Flow | | | | | |
Discounted Cash Flow [Member] | FIA embedded derivatives, included in contractholder funds | | | | | | | |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | | | | | | | |
Valuation Technique | | Discounted cash flow | | | | | |
Discounted Cash Flow [Member] | Minimum [Member] | FIA embedded derivatives, included in contractholder funds | | | | | | | |
Liabilities | | | | | | | |
Surrender rates | | 0.50% | | 0.50% | | | |
Discounted Cash Flow [Member] | Maximum | FIA embedded derivatives, included in contractholder funds | | | | | | | |
Liabilities | | | | | | | |
Surrender rates | | 75.00% | | 75.00% | | | |
Discounted Cash Flow [Member] | Weighted average | FIA embedded derivatives, included in contractholder funds | | | | | | | |
Liabilities | | | | | | | |
Surrender rates | | 10.00% | | 13.00% | | | |
Matrix Pricing [Member] | Funds withheld for reinsurance liability [Member] | | | | | | | |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | | | | | | | |
Valuation Technique | | Matrix pricing | | | | | |
Matrix Pricing [Member] | Minimum [Member] | Funds withheld for reinsurance liability [Member] | | | | | | | |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | | | | | | | |
Fair Value Inputs, Discount Rate | | 98.00% | | 100.00% | | | |
Matrix Pricing [Member] | Maximum | Funds withheld for reinsurance liability [Member] | | | | | | | |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | | | | | | | |
Fair Value Inputs, Discount Rate | | 122.00% | | 122.00% | | | |
Matrix Pricing [Member] | Weighted average | Funds withheld for reinsurance liability [Member] | | | | | | | |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | | | | | | | |
Fair Value Inputs, Discount Rate | | 109.00% | | 112.00% | | | |
Cost Approach Valuation Technique [Member] | Funds withheld for reinsurance liability [Member] | | | | | | | |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | | | | | | | |
Valuation Technique | | Loan Recovery Value | | | | | |
Cost Approach Valuation Technique [Member] | Minimum [Member] | Loan Participations and Assignments [Member] | | | | | | | |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | | | | | | | |
Fair Value Inputs, Discount Rate | | 52.00% | | | | | |
Cost Approach Valuation Technique [Member] | Minimum [Member] | Funds withheld for reinsurance liability [Member] | | | | | | | |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | | | | | | | |
Fair Value Inputs, Discount Rate | | 56.00% | | 6.00% | | | |
Cost Approach Valuation Technique [Member] | Maximum | Loan Participations and Assignments [Member] | | | | | | | |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | | | | | | | |
Fair Value Inputs, Discount Rate | | 100.00% | | | | | |
Cost Approach Valuation Technique [Member] | Maximum | Funds withheld for reinsurance liability [Member] | | | | | | | |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | | | | | | | |
Fair Value Inputs, Discount Rate | | 100.00% | | 12.00% | | | |
Cost Approach Valuation Technique [Member] | Weighted average | Loan Participations and Assignments [Member] | | | | | | | |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | | | | | | | |
Fair Value Inputs, Discount Rate | | 71.00% | | 100.00% | | | |
Cost Approach Valuation Technique [Member] | Weighted average | Funds withheld for reinsurance liability [Member] | | | | | | | |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | | | | | | | |
Fair Value Inputs, Discount Rate | | 82.00% | | 8.00% | | | |
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring | | | | | | | |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | | | | | | | |
Funds Withheld Receivable | | $ 78.1 | | $ 74.7 | | | |
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring | Corporate Debt Securities [Member] | | | | | | | |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | | | | | | | |
Available-for-sale Securities | | 0 | | 14.1 | | | |
Fair Value, Inputs, Level 3 [Member] | FIA embedded derivatives, included in contractholder funds | Fair Value, Measurements, Recurring | | | | | | | |
Liabilities | | | | | | | |
Derivative Liability | | 131.2 | | 142.3 | | | |
Fair Value, Inputs, Level 3 [Member] | Broker Quoted [Member] | Funds Withheld Receivables [Member] | | | | | | | |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | | | | | | | |
Assets, Fair Value Disclosure | | 35.7 | | 6.7 | | | |
Fair Value, Inputs, Level 3 [Member] | Broker Quoted [Member] | Corporate Debt Securities [Member] | | | | | | | |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | | | | | | | |
Assets, Fair Value Disclosure | | 0 | | 14.1 | | | |
Fair Value, Inputs, Level 3 [Member] | Discounted Cash Flow [Member] | Fair Value, Measurements, Recurring | | | | | | | |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | | | | | | | |
Funds Withheld Receivable | | 5.4 | | 19.2 | | | |
Other invested assets | | $ 0 | | 2.8 | | | |
Fair Value, Inputs, Level 3 [Member] | Discounted Cash Flow [Member] | Front Street Future Policyholder Benefits Reserve [Member] | Fair Value, Measurements, Recurring | | | | | | | |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | | | | | | | |
Valuation Technique | | Discounted cash flow | | | | | |
Liabilities | | | | | | | |
Derivative Liability | | $ 631.8 | | 629.2 | | | |
Fair Value, Inputs, Level 3 [Member] | Matrix Pricing [Member] | Funds Withheld Receivables [Member] | | | | | | | |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | | | | | | | |
Assets, Fair Value Disclosure | | 35.2 | | 39.1 | | | |
Fair Value, Inputs, Level 3 [Member] | Cost Approach Valuation Technique [Member] | Funds Withheld Receivables [Member] | | | | | | | |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | | | | | | | |
Assets, Fair Value Disclosure | | 1.8 | | 9.7 | | | |
Other invested assets | Fair Value, Measurements, Recurring | | | | | | | |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | | | | | | | |
Other invested assets | | 0 | | 2.8 | | | |
Other invested assets | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring | Other invested assets | | | | | | | |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | | | | | | | |
Other invested assets | | 0 | | | | | |
Other invested assets | Fair Value, Inputs, Level 3 [Member] | Option Pricing [Member] | Fair Value, Measurements, Recurring | Other invested assets | | | | | | | |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | | | | | | | |
Other invested assets | | | | 2.8 | | | |
Front Street Future Policyholder Benefits Reserve [Member] | | | | | | | |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | | | | | | | |
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value | | 631.8 | | 629.2 | | 151.3 | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings | | 59.5 | | 24.3 | | 7 | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases | | | | 444.2 | | 150.6 | |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements | | $ (56.9) | | $ (9.4) | | $ 6.3 | |
Front Street Future Policyholder Benefits Reserve [Member] | Minimum [Member] | | | | | | | |
Liabilities | | | | | | | |
Non-performance spread | | | | 0.16% | | | |
Risk margin for uncertainty | | | | 0.50% | | | |
Front Street Future Policyholder Benefits Reserve [Member] | Maximum | | | | | | | |
Liabilities | | | | | | | |
Non-performance spread | | | | 0.46% | | | |
Risk margin for uncertainty | | | | 1.00% | | | |
Front Street Future Policyholder Benefits Reserve [Member] | Weighted average | | | | | | | |
Liabilities | | | | | | | |
Non-performance spread | | 0.32% | | | | | |
Risk margin for uncertainty | | 0.50% | | | | | |
| |
[1] | (a) During Fiscal 2016, the net transfer to Level 3 was exclusively from Level 2. The transfers into Level 3 were related to changes in the primary pricing source and changes in the observability of external information used in determining the fair value. | |
[2] | (a) During Fiscal 2015, the net transfer to Level 3 was related to a loan receivable previously classified as a related party loan. | |