Income Taxes (Narrative) (Details) $ / shares in Units, kr in Millions, $ in Millions		6 Months Ended	12 Months Ended
	Dec. 31, 2017 USD ($)	Mar. 29, 2019 USD ($)	Dec. 31, 2019 USD ($) $ / shares	Dec. 31, 2018 USD ($) $ / shares	Dec. 31, 2017 USD ($) $ / shares	Dec. 16, 2019 DKK (kr)	Aug. 27, 2019 DKK (kr)	Dec. 31, 2016 USD ($)	Dec. 10, 2013 DKK (kr)
Discontinued operation, deferred tax assets				$ 131.0
Discontinued operations, deferred tax liabilities				333.0
Net deferred tax liabilities			$ (1,652.2)	$ (2,311.2)
Valuation allowance, deferred tax asset, change in amount			128.0
Basis differences in investments outside the U.S.			$ 9,600.0
Statutory federal income tax rate	21.00%		21.00%	21.00%	35.00%
Effective income tax rate			26.40%	18.80%	14.60%
Effective income tax rate reconciliation, other reconciling items, percent			(6.50%)	(1.20%)	(5.60%)
Income tax payments			$ 847.0	$ 673.0	$ 689.0
Employee service share-based compensation, tax benefit from exercise of stock options			79.0	57.0	85.0
Excess tax benefit from share-based compensation, operating activities			55.0	38.0	55.0
Deferred tax assets, valuation allowances			261.2	389.6
Gross unrecognized tax benefits	$ 736.8		1,180.9	986.0	736.8			$ 992.2
Unrecognized tax benefits, net of offsetting indirect tax benefits				988.0
Unrecognized tax benefits, indirect tax benefits				117.0
Potential interest and penalties				(119.0)
Recognized potential interest and penalties			227.0	41.0	41.0
Unrecognized tax benefits that would impact effective tax rate			1,300.0
Deferred tax asset, other
Deferred tax assets, valuation allowances			32.0
Domestic tax authority | IRS
Proposed adjustments to taxable income, self-insurance, other		$ 2,700.0
Foreign tax authority
Income tax examination, amount of tax assessments 2004-2009			266.0						kr 1,800
Income tax examination, amount of tax assessments 2010-2012			159.0				kr 1,100
Income tax examination, amount of tax assessments 2013-2015			113.0			kr 751
Income tax holiday, aggregate dollar amount			$ 71.0	$ 69.0	$ 62.0
Income tax holiday, income tax benefits per diluted share | $ / shares			$ 0.10	$ 0.10	$ 0.09
United States
Net deferred tax liabilities			$ (1,600.0)	$ (2,000.0)
International
Net deferred tax liabilities			(90.0)	(277.0)
Discontinued operations
Net deferred tax liabilities				$ (202.0)
Continuing operations
Net operating loss carryforwards			504.0
Operating loss carryforwards, valuation allowances			162.0
Gross unrecognized tax benefits			1,200.0
Unrecognized tax benefits, net of offsetting indirect tax benefits			1,400.0
Unrecognized tax benefits, indirect tax benefits			131.0
Potential interest and penalties			(320.0)
Estimated reduction in unrecognized tax benefits within twelve months			(368.0)
Continuing operations | General business and foreign tax credit
Tax credit carryforwards			199.0
Tax credit carryforward, valuation allowance			$ 67.0