Reclassifications Out of Accumulated Other Comprehensive Loss - Reclassifications of Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income tax (expense) benefit		$ 210	$ 77	$ 128
Net income		596	511	395
Interest expense		400	$ 608	$ 848
Reclassifications, net of tax	[1]	(23)
Past service liability
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, before tax	[1],[2]	0
Actuarial losses
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, before tax	[1],[2]	(7)
Amortization of defined benefit pension
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, before tax	[1]	(7)
Tax benefit	[1]	2
Reclassifications, net of tax	[1]	(5)
Reclassification out of Accumulated Other Comprehensive Income (loss) | Unrealized gains on available-for-sale securities
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net gain on securities	[1]	0
Income tax (expense) benefit	[1]	0
Net income	[1]	0
Reclassification out of Accumulated Other Comprehensive Income (loss) | Unrealized gains on cash flow hedges
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income tax (expense) benefit	[1]	7
Net income	[1]	(18)
Interest expense	[1]	$ (25)

[1] Amounts in parentheses indicate expense items.

[2] See Note 14, “Employee Benefits,” for additional information.