Shareholders' Equity - Schedule of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	$ 6,115	$ (3,296)	$ 5,457	$ (3,914)
Other comprehensive income/(loss) before reclassifications	41	(26)	37	286
Amounts reclassified from AOCI	79	21	228	85
Net current period Other comprehensive (loss)/income	120	(5)	265	371
Ending balance	6,562	(8,253)	6,562	(8,253)
Accumulated other comprehensive loss
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(10,132)	(10,539)	(10,277)	(10,915)
Ending balance	(10,012)	(10,544)	(10,012)	(10,544)
Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	36	(70)	64	(178)
Other comprehensive income/(loss) before reclassifications	(1)	(1)	(29)	107
Amounts reclassified from AOCI
Net current period Other comprehensive (loss)/income	(1)	(1)	(29)	107
Ending balance	35	(71)	35	(71)
Unrealized Gains and Losses on Certain Investments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	1	2	2	2
Other comprehensive income/(loss) before reclassifications			(1)
Amounts reclassified from AOCI
Net current period Other comprehensive (loss)/income			(1)
Ending balance	1	2	1	2
Unrealized Gains and Losses on Derivative Instruments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	95	23	88	(211)
Other comprehensive income/(loss) before reclassifications	29	(25)	45	181
Amounts reclassified from AOCI	(1)	4	(10)	32
Net current period Other comprehensive (loss)/income	28	(21)	35	213
Ending balance	123	2	123	2
Defined Benefit Pension Plans & Other Postretirement Benefits
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(10,264)	(10,494)	(10,431)	(10,528)
Other comprehensive income/(loss) before reclassifications	13		22	(2)
Amounts reclassified from AOCI	80	17	238	53
Net current period Other comprehensive (loss)/income	93	17	260	51
Ending balance	$ (10,171)	$ (10,477)	$ (10,171)	$ (10,477)