Investment Securities - Fair Value of Hedge Funds and Private Equity Funds (Details) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Total private equity funds and hedge funds included in other long-term investments
Debt and Equity Securities, FV-NI [Line Items]
Fair Value	$ 239.8	$ 153.8
Unfunded Commitments	102.5	44.0
Private equity funds
Debt and Equity Securities, FV-NI [Line Items]
Fair Value	185.1	141.8
Unfunded Commitments	102.5	44.0
Private equity funds | Aerospace/Defense/Government
Debt and Equity Securities, FV-NI [Line Items]
Fair Value	102.9	69.8
Unfunded Commitments	45.1	11.8
Private equity funds | Financial services
Debt and Equity Securities, FV-NI [Line Items]
Fair Value	77.9	67.7
Unfunded Commitments	54.9	29.3
Private equity funds | Real estate
Debt and Equity Securities, FV-NI [Line Items]
Fair Value	4.3	4.3
Unfunded Commitments	2.5	2.9
Hedge funds
Debt and Equity Securities, FV-NI [Line Items]
Fair Value	54.7	12.0
Unfunded Commitments	0.0	0.0
Hedge funds | Long/short equity financials and business services
Debt and Equity Securities, FV-NI [Line Items]
Fair Value	49.3	0.0
Unfunded Commitments	0.0	0.0
Hedge funds | European small/mid cap
Debt and Equity Securities, FV-NI [Line Items]
Fair Value	5.4	12.0
Unfunded Commitments	$ 0.0	$ 0.0