Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Statement of Comprehensive Income [Abstract]
Net income	$ 5,240.4	$ 6,244.8	$ 5,581.7
Other comprehensive income (loss):
Change in foreign currency translation gains (losses)	(25.8)	(248.1)	13.5
Change in net unrealized gains (losses) on available-for-sale securities	14.1	(53.2)	(15.9)
Change in retirement benefit plans (Note 15)	(776.5)	616.9	2,699.4
Change in net unrealized gains (losses) on cash flow hedges	109.5	432.9	151.6
Other comprehensive income (loss) before income taxes	(678.7)	748.5	2,848.6
Benefit (expense) for income taxes related to other comprehensive income (loss)	196.3	(250.0)	(695.3)
Other comprehensive income (loss), net of tax (Note 17)	(482.4)	498.5	2,153.3
Comprehensive income	$ 4,758.0	$ 6,743.3	$ 7,735.0