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Litigation and Regulatory Matters - Additional Information (Details) $ in Thousands	1 Months Ended		3 Months Ended		9 Months Ended
	Oct. 28, 2019 USD ($)	Sep. 30, 2019 CAD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)
Loss Contingencies [Line Items]
Expense related to various legal matters			$ 13,000,000	$ 3,000,000	$ 16,000,000	$ 513,000,000
Estimate of reasonably possible loss			$ 330,000,000		$ 330,000,000
Supranational, Sovereign and Agency Bonds [Member]
Loss Contingencies [Line Items]
Litigation Settlement, Amount Awarded to Other Party		$ 1,323
Subsequent Event [Member] \| HSBC Bank USA [Member] \| Commodity Futures Trading Commission Investigation [Member]
Loss Contingencies [Line Items]
Civil monetary penalty paid	$ 650,000