Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Statement of Comprehensive Income [Abstract]
Net unrealized gains (losses) on securities available for sale, tax	$ (97)	$ (524)	$ (281)	$ (495)
Net unrealized gains (losses) on derivative financial instruments, tax	(15)	(62)	(120)	(117)
Net pension and postretirement benefit costs, tax	$ 0	$ 0	$ (21)	$ (1)

Amount, after reclassification adjustment, of tax (expense) benefit for (increase) decrease in accumulated other comprehensive income of defined benefit plan.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 45
-Paragraph 10A
-Subparagraph (j)
-SubTopic 10
-Topic 220
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482790/220-10-45-10A

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 45
-Paragraph 10A
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-URI https://asc.fasb.org/1943274/2147482790/220-10-45-10A

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 45
-Paragraph 12
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-Topic 220
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-URI https://asc.fasb.org/1943274/2147482790/220-10-45-12

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 810
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-Name Accounting Standards Codification
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Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 220
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-Name Accounting Standards Codification
-Section 45
-Paragraph 10A
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