Consolidated Statements of Shareholders' Equity - USD ($) shares in Millions, $ in Millions	Total	Common Stock [Member]	Additional Paid In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Balance, beginning (in shares) at Dec. 31, 2014		268.1
Balance, beginning at Dec. 31, 2014	$ 24,251.3	$ 2.7	$ 10,062.3	$ 14,014.4	$ 171.9
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	2,560.0			2,560.0
Other comprehensive income (loss)	(464.5)				(464.5)
Premiums for and settlement of equity options	(14.0)		(14.0)
Repurchase and retirement of common stock, shares		(10.4)
Repurchase and retirement of common stock	(1,515.8)	$ (0.1)	(382.2)	(1,133.5)
Dividends and dividend equivalents	(662.4)			(662.4)
Issuance of common stock under employee stock plans, net of related tax benefits (in shares)		3.5
Issuance of common stock under employee stock plans, net of related tax benefits	308.2		308.2
Convertible debenture repurchases and conversions	(1,287.8)		(1,287.8)
Equity Units contract payments and issuance costs	(130.9)		(130.9)
Balance, ending (in shares) at Dec. 31, 2015		261.2
Balance, ending at Dec. 31, 2015	23,044.1	$ 2.6	8,555.6	14,778.5	(292.6)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	2,469.8			2,469.8
Other comprehensive income (loss)	24.7				24.7
Dividends and dividend equivalents	(687.7)			(687.7)
Issuance of common stock under employee stock plans, net of related tax benefits (in shares)		2.5
Issuance of common stock under employee stock plans, net of related tax benefits	249.2		249.2
Equity units issuance costs adjustment	0.3		0.3
Balance, ending (in shares) at Dec. 31, 2016		263.7
Balance, ending at Dec. 31, 2016	25,100.4	$ 2.6	8,805.1	16,560.6	(267.9)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	3,842.8
Other comprehensive income (loss)	166.4
Premiums for and settlement of equity options	$ 0.9		0.9
Repurchase and retirement of common stock, shares	(10.5)	(10.5)
Repurchase and retirement of common stock	$ (1,997.7)		(356.1)	(1,641.6)
Dividends and dividend equivalents	(707.4)			(707.4)
Issuance of common stock under employee stock plans, net of related tax benefits (in shares)		2.9
Issuance of common stock under employee stock plans, net of related tax benefits	342.5		342.5
Convertible debenture repurchases and conversions	(245.0)		(245.0)
Balance, ending (in shares) at Dec. 31, 2017		256.1
Balance, ending at Dec. 31, 2017	$ 26,502.9	$ 2.6	$ 8,547.4	$ 18,054.4	$ (101.5)