Revenues (Revenue by Segment) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Hedging gains (losses)	$ 176	$ 455	$ (138)
Total revenues	182,527	161,857	136,819
Google Services
Segment Reporting Information [Line Items]
Revenues from contract with customer	168,635	151,825	130,524
Google Services | Google Search & other
Segment Reporting Information [Line Items]
Revenues from contract with customer	104,062	98,115	85,296
Google Services | YouTube ads
Segment Reporting Information [Line Items]
Revenues from contract with customer	19,772	15,149	11,155
Google Services | Google Network Members' properties
Segment Reporting Information [Line Items]
Revenues from contract with customer	23,090	21,547	20,010
Google Services | Google advertising
Segment Reporting Information [Line Items]
Revenues from contract with customer	146,924	134,811	116,461
Google Services | Google other
Segment Reporting Information [Line Items]
Revenues from contract with customer	21,711	17,014	14,063
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