Information about Segments and Geographic Areas (Revenue and Operating Income/Loss by Segment) (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 ($)
Segment Reporting Information [Line Items]
Hedging gains (losses)										$ 176	$ 455	$ (138)
Total revenues										182,527	161,857	136,819
Segment operating income / (loss)										41,224	34,231	27,524
European Commission fines										0	1,697	5,071
Unfavorable Regulatory Action
Segment Reporting Information [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
Google Services
Segment Reporting Information [Line Items]
Revenues from contract with customer										168,635	151,825	130,524
Google Cloud
Segment Reporting Information [Line Items]
Revenues from contract with customer										13,059	8,918	5,838
Other Bets
Segment Reporting Information [Line Items]
Revenues from contract with customer										657	659	595
Operating Segments | Google Services
Segment Reporting Information [Line Items]
Segment operating income / (loss)										54,606	48,999	43,137
Operating Segments | Google Cloud
Segment Reporting Information [Line Items]
Segment operating income / (loss)										(5,607)	(4,645)	(4,348)
Operating Segments | Other Bets
Segment Reporting Information [Line Items]
Segment operating income / (loss)										(4,476)	(4,824)	(3,358)
Reconciling items
Segment Reporting Information [Line Items]
Segment operating income / (loss)										$ (3,299)	$ (5,299)	$ (7,907)