Commitments and Contingencies (Narrative) (Details) $ in Millions, € in Billions							3 Months Ended			12 Months Ended
	Mar. 20, 2019 USD ($)	Mar. 20, 2019 EUR (€)	Jun. 30, 2018 USD ($)	Jun. 30, 2018 EUR (€)	Jun. 27, 2017 USD ($)	Jun. 27, 2017 EUR (€)	Mar. 31, 2019 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Commitments and Contingencies Disclosure [Line Items]
Other non-cancelable contractual obligations										$ 10,700
European Commission fines										$ 0	$ 1,697	$ 5,071
European Commission Antitrust Investigation
Commitments and Contingencies Disclosure [Line Items]
European Commission fines	$ 1,700	€ 1.5	$ 5,100	€ 4.3	$ 2,700	€ 2.4	$ 1,700	$ 5,100	$ 2,700		$ 2,300	$ 5,100