Commitments and Contingencies - Litigation and Regulatory Matters (Details) - USD ($)		3 Months Ended		9 Months Ended
	Jun. 25, 2019	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Loss Contingencies [Line Items]
Litigation settlement expense		$ 352,000,000	$ 90,000,000	$ 539,000,000	$ 292,000,000
Minimum
Loss Contingencies [Line Items]
Estimated range of possible loss		0		0
Maximum
Loss Contingencies [Line Items]
Estimated range of possible loss		$ 1,800,000,000		$ 1,800,000,000
Precious Metals Trading
Loss Contingencies [Line Items]
Settlement payment	$ 36,500,000