CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) (Parenthetical) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement of Comprehensive Income [Abstract]
Net unrealized derivative instrument gains arising during the periods, tax	$ 0	$ (1)	$ 30	$ 35
Reclassification adjustment for net derivative (gains) losses included in net income, tax	(15)	4	(27)	13
Net unrealized debt securities gains arising during the periods, tax	(14)	13	131	165
Other-than-temporary impairment not recognized in earnings on debt securities, tax	0	0	0	0
Reclassification of net debt securities gains to net income, tax	0	0	(1)	(3)
Amortization of actuarial loss, tax	$ 1	$ 2	$ 2	$ 5

Amount, before reclassification, of tax expense (benefit) for gain (loss) from derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness.

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Amount of tax expense (benefit) for reclassification of gain (loss) from accumulated other comprehensive income (AOCI) for derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness.

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Amount of tax expense (benefit) 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) of reclassification adjustment from accumulated other comprehensive income (loss) for gain (loss) of defined benefit plan.

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Amount, before adjustment, of tax expense (benefit) for unrealized holding gain (loss) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). Excludes tax expense (benefit) for unrealized gain (loss) on investment in debt security measured at amortized cost (held-to-maturity) from transfer to available-for-sale.

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Amount of tax (expense) benefit of other than temporary impairment loss (OTTI) on investments in available-for-sale and held-to-maturity debt securities, recognized in other comprehensive loss and attributable to parent entity.

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