Subsequent Events (Details)	3 Months Ended		6 Months Ended
	Dec. 31, 2023 USD ($) $ / shares	Dec. 31, 2022 USD ($)	Dec. 31, 2023 USD ($) $ / shares	Dec. 31, 2022 USD ($)	Jun. 30, 2024 USD ($)	Feb. 05, 2024 USD ($) $ / shares	Jan. 31, 2024 USD ($)	Sep. 30, 2023 USD ($)	Jun. 30, 2023 USD ($) $ / shares	Sep. 30, 2022 USD ($)	Jun. 30, 2022 USD ($)
Subsequent Event
Unrecognized Tax Benefits, Including Income Tax Penalties and Interest Accrued									$ 4,000,000
Assets	$ 9,988,000,000		$ 9,988,000,000		$ 10,508,000,000				10,777,000,000
Other comprehensive income/(loss) before reclassifications	30,000,000	$ 118,000,000	(4,000,000)	$ (3,000,000)
Foreign currency translation adjustments	37,000,000	118,000,000	(2,000,000)	(17,000,000)
Net change in derivatives and hedges, net of tax	(7,000,000)	0	(2,000,000)	14,000,000
Available for sale investments	0	1,000,000	0	2,000,000
Other Comprehensive Income, Other, Net of Tax	34,000,000	119,000,000	0	(1,000,000)
Accumulated other comprehensive income/(loss)	(354,000,000)	(395,000,000)	(354,000,000)	(395,000,000)				$ (388,000,000)	$ (354,000,000)	$ (514,000,000)	$ (394,000,000)
Amounts reclassified from accumulated other comprehensive income/(loss)	4,000,000	(1,000,000)	(4,000,000)	(2,000,000)
Pension and other post-retirement adjustments	$ 4,000,000	0	4,000,000	0
Tax expense/(benefit)		0	$ 0	1,000,000
Restructuring and Related Cost, Expected Cost							$ 25
Common Stock, Par or Stated Value Per Share | $ / shares	$ 0.01		$ 0.01			$ 0.01			$ 0.01
Business Combination, Termination Fee						$ 345
Merger Agreement
Subsequent Event
Business Combination, Purchase Price per Share | $ / shares						$ 63.5
Business Combination, Enterprise Value						16,500,000,000
Accumulated Translation Adjustment [Member]
Subsequent Event
Other comprehensive income/(loss) before reclassifications	$ 37,000,000	118,000,000	$ (2,000,000)	(17,000,000)
Foreign currency translation adjustments		118,000,000
Accumulated other comprehensive income/(loss)	(348,000,000)	(395,000,000)	(348,000,000)	(395,000,000)				(385,000,000)	$ (346,000,000)	(513,000,000)	(378,000,000)
Amounts reclassified from accumulated other comprehensive income/(loss)	0
AOCI, Derivative Qualifying as Hedge, Parent [Member]
Subsequent Event
Other comprehensive income/(loss) before reclassifications	(7,000,000)	0		14,000,000
Net change in derivatives and hedges, net of tax		0
Accumulated other comprehensive income/(loss)	43,000,000	41,000,000	43,000,000	41,000,000				50,000,000	45,000,000	41,000,000	27,000,000
Amounts reclassified from accumulated other comprehensive income/(loss)	0
ACOI, Accumulated Gain (Loss), Marketable Securities [Member]
Subsequent Event
Other comprehensive income/(loss) before reclassifications		0
Net change in derivatives and hedges, net of tax	(7,000,000)
Available for sale investments		1,000,000	0	2,000,000
Accumulated other comprehensive income/(loss)		(2,000,000)		(2,000,000)						(3,000,000)	(4,000,000)
Amounts reclassified from accumulated other comprehensive income/(loss)	0	1,000,000	0	2,000,000
Accumulated Defined Benefit Plans Adjustment [Member]
Subsequent Event
Other comprehensive income/(loss) before reclassifications	0
Accumulated other comprehensive income/(loss)	(48,000,000)	(38,000,000)	(48,000,000)	(38,000,000)				(52,000,000)	(52,000,000)	(38,000,000)	$ (38,000,000)
Amounts reclassified from accumulated other comprehensive income/(loss)	4,000,000	0
Pension and other post-retirement adjustments	4,000,000	0	(4,000,000)
Available-for-sale Securities [Member]
Subsequent Event
Other comprehensive income/(loss) before reclassifications	0
Other Comprehensive Income, Other, Net of Tax	0
Accumulated other comprehensive income/(loss)	(1,000,000)	(1,000,000)	(1,000,000)	(1,000,000)				$ (1,000,000)	(1,000,000)	$ (1,000,000)
Amounts reclassified from accumulated other comprehensive income/(loss)	0
PharmaConsumerHealth
Subsequent Event
Segment EBITDA	126,000,000	$ 135,000,000	227,000,000	$ 243,000,000
Assets	$ 4,517,000,000		$ 4,517,000,000						$ 4,867,000,000