Derivative and Hedging Activities - Derivatives Subject to a Master Netting Arrangement (Details) - USD ($) $ in Millions	Jun. 30, 2025	Dec. 31, 2024
Derivatives designated as hedging instruments: | Interest rate swaps | Interest rate swaps (fair value hedge)
Assets
Gross Amounts Not Offset in the Statements of Condition	$ 0
Cash Collateral Pledged (Received)	66
Derivatives designated as hedging instruments: | Interest rate swaps | Interest rate caps (cash flow hedge)
Assets
Gross Amounts Not Offset in the Statements of Condition	0
Cash Collateral Pledged (Received)	0
Derivatives not designated as hedging instruments:
Assets
Gross Amounts Not Offset in the Statements of Condition	17	$ 22
Cash Collateral Pledged (Received)	(1)	(5)
Liabilities
Gross Amounts Not Offset in the Statements of Condition	27	32
Cash Collateral Pledged (Received)	39	57
Derivatives not designated as hedging instruments: | Interest rate swaps
Liabilities
Gross Amounts Not Offset in the Statements of Condition	22	30
Cash Collateral Pledged (Received)	38	47
Derivatives not designated as hedging instruments: | Mortgage-backed securities forwards
Assets
Gross Amounts Not Offset in the Statements of Condition		7
Cash Collateral Pledged (Received)		(2)
Liabilities
Gross Amounts Not Offset in the Statements of Condition	5	2
Cash Collateral Pledged (Received)	1	10
Derivatives not designated as hedging instruments: | Interest rate swaptions
Assets
Gross Amounts Not Offset in the Statements of Condition	17	15
Cash Collateral Pledged (Received)	$ (1)	$ (3)