Shareholders' Equity - Schedule of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	$ 5,457	$ (3,914)
Other comprehensive (loss)/income before reclassifications	(63)	114
Amounts reclassified from AOCI	74	41
Net current period Other comprehensive (loss)/income	11	155
Ending balance	5,987	(3,325)
Accumulated other comprehensive loss
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(10,277)	(10,915)
Ending balance	(10,266)	(10,760)
Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	64	(178)
Other comprehensive (loss)/income before reclassifications	(63)	46
Amounts reclassified from AOCI
Net current period Other comprehensive (loss)/income	(63)	46
Ending balance	1	(132)
Unrealized Gains and Losses on Certain Investments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	2	2
Other comprehensive (loss)/income before reclassifications	(1)
Amounts reclassified from AOCI
Net current period Other comprehensive (loss)/income	(1)
Ending balance	1	2
Unrealized Gains and Losses on Derivative Instruments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	88	(211)
Other comprehensive (loss)/income before reclassifications	(8)	68
Amounts reclassified from AOCI	(6)	18
Net current period Other comprehensive (loss)/income	(14)	86
Ending balance	74	(125)
Defined Benefit Pension Plans & Other Postretirement Benefits
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(10,431)	(10,528)
Other comprehensive (loss)/income before reclassifications	9
Amounts reclassified from AOCI	80	23
Net current period Other comprehensive (loss)/income	89	23
Ending balance	$ (10,342)	$ (10,505)