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Fair Value Measures - Financial Instruments Carried at Fair Value (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Assets:
Total debt securities available for sale	$ 7,599	$ 9,060
Total securities	7,613	9,074
Mortgage servicing rights	1,034	1,033
Total debt securities available for sale
Assets:
Total debt securities available for sale	7,599	9,060
Total mortgage-related debt securities
Assets:
Total debt securities available for sale	4,716	4,789
Total mortgage-related debt securities | GSE certificates
Assets:
Total debt securities available for sale	1,246	1,297
Total mortgage-related debt securities | GSE CMOs
Assets:
Total debt securities available for sale	3,282	3,301
Total mortgage-related debt securities | Private Label CMOs
Assets:
Total debt securities available for sale	188	191
Total other debt securities
Assets:
Total debt securities available for sale	2,883	4,271
Total other debt securities | U. S. Treasury obligations
Assets:
Total debt securities available for sale	0	1,487
Total other debt securities | GSE debentures
Assets:
Total debt securities available for sale	1,589	1,398
Total other debt securities | Asset-backed securities
Assets:
Total debt securities available for sale	335	361
Total other debt securities | Municipal bonds
Assets:
Total debt securities available for sale	18	30
Total other debt securities | Corporate bonds
Assets:
Total debt securities available for sale	833	885
Total other debt securities | Foreign notes
Assets:
Total debt securities available for sale	19	20
Total other debt securities | Capital trust notes
Assets:
Total debt securities available for sale	89	90
Recurring
Assets:
Total securities	7,613	9,074
Residential first mortgage loans	1,305	1,115
Mortgage servicing rights	1,034	1,033
Total assets at fair value	10,131	11,451
Liabilities:
Total liabilities at fair value	70	136
Recurring | Interest rate swaps and swaptions
Assets:
Derivative assets	159	182
Liabilities:
Derivative liabilities	49	65
Recurring | Futures
Assets:
Derivative assets	0	2
Recurring | Rate lock commitments
Assets:
Derivative assets	15	9
Liabilities:
Derivative liabilities	7	10
Recurring | Mortgage-backed securities forwards
Assets:
Derivative assets	5	36
Liabilities:
Derivative liabilities	14	61
Recurring | Total debt securities available for sale
Assets:
Total debt securities available for sale	7,599	9,060
Recurring | Total mortgage-related debt securities
Assets:
Total debt securities available for sale	4,716	4,789
Recurring | Total mortgage-related debt securities | GSE certificates
Assets:
Total debt securities available for sale	1,246	1,297
Recurring | Total mortgage-related debt securities | GSE CMOs
Assets:
Total debt securities available for sale	3,282	3,301
Recurring | Total mortgage-related debt securities | Private Label CMOs
Assets:
Total debt securities available for sale	188	191
Recurring | Total other debt securities
Assets:
Total debt securities available for sale	2,883	4,271
Recurring | Total other debt securities | U. S. Treasury obligations
Assets:
Total debt securities available for sale		1,487
Recurring | Total other debt securities | GSE debentures
Assets:
Total debt securities available for sale	1,589	1,398
Recurring | Total other debt securities | Asset-backed securities
Assets:
Total debt securities available for sale	335	361
Recurring | Total other debt securities | Municipal bonds
Assets:
Total debt securities available for sale	18	30
Recurring | Total other debt securities | Corporate bonds
Assets:
Total debt securities available for sale	833	885
Recurring | Total other debt securities | Foreign notes
Assets:
Total debt securities available for sale	19	20
Recurring | Total other debt securities | Capital trust notes
Assets:
Total debt securities available for sale	89	90
Recurring | Total equity securities
Assets:
Total equity securities	14	14
Recurring | Total equity securities | Mutual funds and common stock
Assets:
Total equity securities	14	14
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Total securities	0	1,487
Residential first mortgage loans	0	0
Mortgage servicing rights	0	0
Total assets at fair value	0	1,487
Liabilities:
Total liabilities at fair value	0	0
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Interest rate swaps and swaptions
Assets:
Derivative assets	0	0
Liabilities:
Derivative liabilities	0	0
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Futures
Assets:
Derivative assets	0	0
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Rate lock commitments
Assets:
Derivative assets	0	0
Liabilities:
Derivative liabilities	0	0
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Mortgage-backed securities forwards
Assets:
Derivative assets	0	0
Liabilities:
Derivative liabilities	0	0
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Total debt securities available for sale
Assets:
Total debt securities available for sale	0	1,487
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Total mortgage-related debt securities
Assets:
Total debt securities available for sale	0	0
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Total mortgage-related debt securities | GSE certificates
Assets:
Total debt securities available for sale	0	0
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Total mortgage-related debt securities | GSE CMOs
Assets:
Total debt securities available for sale	0	0
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Total mortgage-related debt securities | Private Label CMOs
Assets:
Total debt securities available for sale	0	0
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Total other debt securities
Assets:
Total debt securities available for sale	0	1,487
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Total other debt securities | U. S. Treasury obligations
Assets:
Total debt securities available for sale		1,487
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Total other debt securities | GSE debentures
Assets:
Total debt securities available for sale	0	0
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Total other debt securities | Asset-backed securities
Assets:
Total debt securities available for sale	0	0
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Total other debt securities | Municipal bonds
Assets:
Total debt securities available for sale	0	0
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Total other debt securities | Corporate bonds
Assets:
Total debt securities available for sale	0	0
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Total other debt securities | Foreign notes
Assets:
Total debt securities available for sale	0	0
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Total other debt securities | Capital trust notes
Assets:
Total debt securities available for sale	0	0
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Total equity securities
Assets:
Total equity securities	0	0
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Total equity securities | Mutual funds and common stock
Assets:
Total equity securities	0	0
Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Total securities	7,613	7,587
Residential first mortgage loans	1,305	1,115
Mortgage servicing rights	0	0
Total assets at fair value	9,082	8,922
Liabilities:
Total liabilities at fair value	63	126
Recurring | Significant Other Observable Inputs (Level 2) | Interest rate swaps and swaptions
Assets:
Derivative assets	159	182
Liabilities:
Derivative liabilities	49	65
Recurring | Significant Other Observable Inputs (Level 2) | Futures
Assets:
Derivative assets	0	2
Recurring | Significant Other Observable Inputs (Level 2) | Rate lock commitments
Assets:
Derivative assets	0	0
Liabilities:
Derivative liabilities	0	0
Recurring | Significant Other Observable Inputs (Level 2) | Mortgage-backed securities forwards
Assets:
Derivative assets	5	36
Liabilities:
Derivative liabilities	14	61
Recurring | Significant Other Observable Inputs (Level 2) | Total debt securities available for sale
Assets:
Total debt securities available for sale	7,599	7,573
Recurring | Significant Other Observable Inputs (Level 2) | Total mortgage-related debt securities
Assets:
Total debt securities available for sale	4,716	4,789
Recurring | Significant Other Observable Inputs (Level 2) | Total mortgage-related debt securities | GSE certificates
Assets:
Total debt securities available for sale	1,246	1,297
Recurring | Significant Other Observable Inputs (Level 2) | Total mortgage-related debt securities | GSE CMOs
Assets:
Total debt securities available for sale	3,282	3,301
Recurring | Significant Other Observable Inputs (Level 2) | Total mortgage-related debt securities | Private Label CMOs
Assets:
Total debt securities available for sale	188	191
Recurring | Significant Other Observable Inputs (Level 2) | Total other debt securities
Assets:
Total debt securities available for sale	2,883	2,784
Recurring | Significant Other Observable Inputs (Level 2) | Total other debt securities | U. S. Treasury obligations
Assets:
Total debt securities available for sale		0
Recurring | Significant Other Observable Inputs (Level 2) | Total other debt securities | GSE debentures
Assets:
Total debt securities available for sale	1,589	1,398
Recurring | Significant Other Observable Inputs (Level 2) | Total other debt securities | Asset-backed securities
Assets:
Total debt securities available for sale	335	361
Recurring | Significant Other Observable Inputs (Level 2) | Total other debt securities | Municipal bonds
Assets:
Total debt securities available for sale	18	30
Recurring | Significant Other Observable Inputs (Level 2) | Total other debt securities | Corporate bonds
Assets:
Total debt securities available for sale	833	885
Recurring | Significant Other Observable Inputs (Level 2) | Total other debt securities | Foreign notes
Assets:
Total debt securities available for sale	19	20
Recurring | Significant Other Observable Inputs (Level 2) | Total other debt securities | Capital trust notes
Assets:
Total debt securities available for sale	89	90
Recurring | Significant Other Observable Inputs (Level 2) | Total equity securities
Assets:
Total equity securities	14	14
Recurring | Significant Other Observable Inputs (Level 2) | Total equity securities | Mutual funds and common stock
Assets:
Total equity securities	14	14
Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Total securities	0	0
Residential first mortgage loans	0	0
Mortgage servicing rights	1,034	1,033
Total assets at fair value	1,049	1,042
Liabilities:
Total liabilities at fair value	7	10
Recurring | Significant Unobservable Inputs (Level 3) | Interest rate swaps and swaptions
Assets:
Derivative assets	0	0
Liabilities:
Derivative liabilities	0	0
Recurring | Significant Unobservable Inputs (Level 3) | Futures
Assets:
Derivative assets	0	0
Recurring | Significant Unobservable Inputs (Level 3) | Rate lock commitments
Assets:
Derivative assets	15	9
Liabilities:
Derivative liabilities	7	10
Recurring | Significant Unobservable Inputs (Level 3) | Mortgage-backed securities forwards
Assets:
Derivative assets	0	0
Liabilities:
Derivative liabilities	0	0
Recurring | Significant Unobservable Inputs (Level 3) | Total debt securities available for sale
Assets:
Total debt securities available for sale	0	0
Recurring | Significant Unobservable Inputs (Level 3) | Total mortgage-related debt securities
Assets:
Total debt securities available for sale	0	0
Recurring | Significant Unobservable Inputs (Level 3) | Total mortgage-related debt securities | GSE certificates
Assets:
Total debt securities available for sale	0	0
Recurring | Significant Unobservable Inputs (Level 3) | Total mortgage-related debt securities | GSE CMOs
Assets:
Total debt securities available for sale	0	0
Recurring | Significant Unobservable Inputs (Level 3) | Total mortgage-related debt securities | Private Label CMOs
Assets:
Total debt securities available for sale	0	0
Recurring | Significant Unobservable Inputs (Level 3) | Total other debt securities
Assets:
Total debt securities available for sale	0	0
Recurring | Significant Unobservable Inputs (Level 3) | Total other debt securities | U. S. Treasury obligations
Assets:
Total debt securities available for sale		0
Recurring | Significant Unobservable Inputs (Level 3) | Total other debt securities | GSE debentures
Assets:
Total debt securities available for sale	0	0
Recurring | Significant Unobservable Inputs (Level 3) | Total other debt securities | Asset-backed securities
Assets:
Total debt securities available for sale	0	0
Recurring | Significant Unobservable Inputs (Level 3) | Total other debt securities | Municipal bonds
Assets:
Total debt securities available for sale	0	0
Recurring | Significant Unobservable Inputs (Level 3) | Total other debt securities | Corporate bonds
Assets:
Total debt securities available for sale	0	0
Recurring | Significant Unobservable Inputs (Level 3) | Total other debt securities | Foreign notes
Assets:
Total debt securities available for sale	0	0
Recurring | Significant Unobservable Inputs (Level 3) | Total other debt securities | Capital trust notes
Assets:
Total debt securities available for sale	0	0
Recurring | Significant Unobservable Inputs (Level 3) | Total equity securities
Assets:
Total equity securities	0	0
Recurring | Significant Unobservable Inputs (Level 3) | Total equity securities | Mutual funds and common stock
Assets:
Total equity securities	$ 0	$ 0

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- Definition

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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