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Restructuring Costs (Restructuring Activities) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025	Dec. 31, 2025
Restructuring Reserve [Roll Forward]
Liability at beginning of period			$ 129	$ 117	$ 117
Restructuring charges	$ 79	$ 46	182	96	222
Cash payments			(222)		(205)
Non-cash charges			(8)		(5)
Liability at end of period	81		81		129
Severance
Restructuring Reserve [Roll Forward]
Liability at beginning of period			99	75	75
Restructuring charges			113		174
Cash payments			(159)		(150)
Non-cash charges			0		0
Liability at end of period	53		53		99
Real Estate Related Costs
Restructuring Reserve [Roll Forward]
Liability at beginning of period			30	42	42
Restructuring charges			22		32
Cash payments			(16)		(39)
Non-cash charges			(8)		(5)
Liability at end of period	28		28		30
Information Technology
Restructuring Reserve [Roll Forward]
Liability at beginning of period			0	0	0
Restructuring charges			0		0
Cash payments			0		0
Non-cash charges			0		0
Liability at end of period	0		0		0
Consulting and Other Outside Services
Restructuring Reserve [Roll Forward]
Liability at beginning of period			0	$ 0	0
Restructuring charges			47		16
Cash payments			(47)		(16)
Non-cash charges			0		0
Liability at end of period	$ 0		$ 0		$ 0