Commitments and Contingent Liabilities - Summary of Off-Balance Sheet Financial Instruments (Details) - USD ($)	Sep. 30, 2021	Dec. 31, 2020
Loss Contingencies [Line Items]
ONE YEAR AND LESS	$ 191,572,500,000	$ 170,021,200,000
OVER ONE YEAR	19,051,400,000	18,441,500,000
TOTAL	210,623,900,000	188,462,700,000
Guarantees to sponsored member programs		0
Undrawn Commitments to Extend Credit
Loss Contingencies [Line Items]
Commitments, participated to others	365,900,000	384,700,000
Custody Securities Lent with Indemnification
Loss Contingencies [Line Items]
ONE YEAR AND LESS	180,619,400,000	157,478,000,000
OVER ONE YEAR	0	0
TOTAL	180,619,400,000	157,478,000,000
Secured by Cash Deposits or Participated to Others | Standby Letters of Credit
Loss Contingencies [Line Items]
TOTAL	33,500,000	24,200,000
Standby Letter of Credit and Financial Guarantee
Loss Contingencies [Line Items]
Guarantor obligations, current carrying value	509,000,000
Undrawn Commitments to Extend Credit
Loss Contingencies [Line Items]
ONE YEAR AND LESS	9,152,600,000	11,260,500,000
OVER ONE YEAR	18,597,600,000	17,678,000,000
TOTAL	27,750,200,000	28,938,500,000
Standby Letters of Credit
Loss Contingencies [Line Items]
ONE YEAR AND LESS	1,727,400,000	1,228,100,000
OVER ONE YEAR	453,800,000	763,500,000
TOTAL	2,181,200,000	1,991,600,000
Commercial Letters of Credit
Loss Contingencies [Line Items]
ONE YEAR AND LESS	73,100,000	54,600,000
OVER ONE YEAR	0	0
TOTAL	$ 73,100,000	$ 54,600,000