Accumulated Other Comprehensive Loss - Changes in AOCL, After Tax and Minority Interest (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	$ 4,823	$ 4,779
Ending balance	3,178	4,825
Total
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(3,844)	(3,835)
Other comprehensive income (loss) before reclassifications	(13)	4
Amounts reclassified from accumulated other comprehensive income (loss)	151	59
Ending balance	(3,706)	(3,772)
Foreign Currency Translation Adjustment
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(1,705)	(1,613)
Other comprehensive income (loss) before reclassifications	(10)	(24)
Amounts reclassified from accumulated other comprehensive income (loss)	8	0
Ending balance	(1,707)	(1,637)
Unrealized Gains (Losses) from Securities
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	1	1
Other comprehensive income (loss) before reclassifications	0	0
Amounts reclassified from accumulated other comprehensive income (loss)	0	0
Ending balance	1	1
Unrecognized Net Actuarial Losses and Prior Service Costs
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(2,140)	(2,224)
Other comprehensive income (loss) before reclassifications	(3)	28
Amounts reclassified from accumulated other comprehensive income (loss)	143	58
Ending balance	(2,000)	(2,138)
Deferred Derivative Gains (Losses)
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	0	1
Other comprehensive income (loss) before reclassifications	0	0
Amounts reclassified from accumulated other comprehensive income (loss)	0	1
Ending balance	$ 0	$ 2