Pledged Assets and Collateral - Pledged Assets and Collateral (Details) - USD ($) $ in Billions	Dec. 31, 2020	Dec. 31, 2019
Significant components of assets pledged
Assets that may be sold or repledged or otherwise used by secured parties	$ 166.6	$ 125.2
Assets that may not be sold or repledged or otherwise used by secured parties	113.9	80.2
Total pledged assets	735.8	684.3
Collateral Received that Can be Resold or Repledged
Collateral permitted to be sold or repledged, delivered, or otherwise used	1,451.7	1,282.5
Collateral sold, repledged, delivered or otherwise used	1,038.9	1,000.5
Investment securities
Significant components of assets pledged
Total pledged assets	80.2	35.9
Loans
Significant components of assets pledged
Total pledged assets	420.5	460.4
Trading assets and other
Significant components of assets pledged
Total pledged assets	235.1	188.0
Assets pledged at Federal Reserve banks and FHLBs
Significant components of assets pledged
Total pledged assets	$ 455.3	$ 478.9