Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 951	$ 923	$ 2,852	$ 2,572
Change in net unrealized gain (loss) on available for sale securities:
Net unrealized gain (loss)	51	(43)	496	(184)
Other reclassifications included in other revenue	(1)	0	(5)	0
Amortization of amounts previously recorded upon transfer to held to maturity from available for sale	10	8	30	26
Other comprehensive income (loss), before tax	60	(35)	521	(158)
Income tax effect	(15)	9	(125)	39
Other comprehensive income (loss), net of tax	45	(26)	396	(119)
Comprehensive Income	$ 996	$ 897	$ 3,248	$ 2,453

Other Comprehensive Loss, Held-to-maturity Security, Transferred From Available for Sale, Amortization, Before Tax

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Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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Amount before tax, after reclassification adjustments of other comprehensive income (loss).

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Amount after tax and reclassification adjustments of other comprehensive income (loss).

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Amount before tax of reclassification adjustment from accumulated other comprehensive income for unrealized gain (loss) realized upon the sale of available-for-sale securities.

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Amount of tax expense (benefit) allocated to other comprehensive income (loss).

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Amount before tax and reclassification adjustments of unrealized holding gain (loss) on available-for-sale securities.

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