Restructuring Activities - Schedule of Restructuring Activities (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Dec. 31, 2023	Sep. 30, 2023	Mar. 31, 2023
Restructuring Cost and Reserve [Line Items]
Restructuring, Incurred Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Restructuring (See Note 7)
Restructuring Reserve [Roll Forward]
Charges to operations	$ 3	$ 155
Charges settled in cash	(37)	(10)
Non-cash items		(110)
Restructuring reserve	1		$ 35
Acquisition Related Intangibles Impairments and Other Charges
Restructuring Reserve [Roll Forward]
Charges to operations	0	68
Charges settled in cash	(2)	0
Non-cash items		(66)
Restructuring reserve	0		2
Workforce
Restructuring Reserve [Roll Forward]
Charges to operations	3	43
Charges settled in cash	(35)	(10)
Non-cash items		0
Restructuring reserve	1		33
Office Space Reductions
Restructuring Reserve [Roll Forward]
Charges to operations	0	44
Charges settled in cash	0	0
Non-cash items		$ (44)
Restructuring reserve	$ 0		$ 0