Equity (Summary of Changes in AOCI) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax	$ (440)	$ (1,005)	$ 49	$ 710
Other comprehensive (loss) income, net - Foreign Currency Translation	562	(1,050)	(647)
Amounts reclassified, pretax - Foreign Currency Translation	0	2	0
Tax benefit (expense)	3	(6)	(14)
Accumulated Other Comprehensive Income (Loss), Defined Benefit Plan, after Tax	(2,026)	(782)	(1,828)	(4,483)
Other Comprehensive Income (Loss), Defined Benefit Plan, before Reclassification Adjustment and Tax	(1,041)	1,225	3,210
Other Comprehensive Income (Loss), Defined Benefit Plan, Reclassification Adjustment from AOCI, before Tax	(568)	129	258
Other Comprehensive Income (Loss), Defined Benefit Plan, after Reclassification Adjustment, Tax	365	(308)	(813)
AOCI, Cash Flow Hedge, Cumulative Gain (Loss), after Tax	47	(231)	(136)	39
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax	278	(246)	(226)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax	80	103	(28)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, Tax	(80)	48	79
Accumulated Other Comprehensive Income (Loss), Net of Tax	(2,419)	(2,018)	(1,915)	$ (3,734)
Other comprehensive (loss) income before reclassifications, net	(201)	(71)	2,337
Amounts reclassified, pretax	(488)	234	230
Other Comprehensive Income (Loss), Tax	$ 288	$ (266)	$ (748)