Segment Information - Summary of Reconciliation of Segment Operating Revenues (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Segment Reporting, Revenue Reconciling Item [Line Items]
Operating Revenues	$ 136,835	$ 133,613	$ 128,292
Operating Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Operating Revenues	134,578	126,342	119,495
Corporate and other
Segment Reporting, Revenue Reconciling Item [Line Items]
Operating Revenues	2,510	7,722	9,334
Eliminations
Segment Reporting, Revenue Reconciling Item [Line Items]
Operating Revenues	$ (253)	$ (451)	$ (537)