Shareholders' Equity - Schedule of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	$ (3,914)	$ (17,228)
Other comprehensive (loss)/income before reclassifications	114	(114)
Amounts reclassified from AOCI	41	7
Net current period Other comprehensive income	155	(107)
Ending balance	(3,325)	(17,016)
Other comprehensive (income) loss, defined benefit plan, reclassification adjustment from AOCI, after tax	23	0
Other comprehensive (income) loss, defined benefit plan, reclassification adjustment from AOCI, tax	(2)	0
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(10,915)	(10,305)
Ending balance	(10,760)	(10,412)
Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(178)	(134)
Other comprehensive (loss)/income before reclassifications	46	(35)
Amounts reclassified from AOCI
Net current period Other comprehensive income	46	(35)
Ending balance	(132)	(169)
Unrealized Gains and Losses on Certain Investments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	2	2
Other comprehensive (loss)/income before reclassifications
Amounts reclassified from AOCI
Net current period Other comprehensive income
Ending balance	2	2
Unrealized Gains and Losses on Derivative Instruments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(211)	12
Other comprehensive (loss)/income before reclassifications	68	(65)
Amounts reclassified from AOCI	18	7
Net current period Other comprehensive income	86	(58)
Ending balance	(125)	(46)
Defined Benefit Pension Plans & Other Postretirement Benefits
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(10,528)	(10,185)
Other comprehensive (loss)/income before reclassifications		(14)
Amounts reclassified from AOCI	23
Net current period Other comprehensive income	23	(14)
Ending balance	$ (10,505)	$ (10,199)