Nature of Operations and Summary of Significant Accounting Policies (Policies)	3 Months Ended
Mar. 31, 2019
Accounting Policies [Abstract]
Nature of Operations	Nature of Operations Google was incorporated in California in September 1998 and re-incorporated in the State of Delaware in August 2003. In 2015, we implemented a holding company reorganization, and as a result, Alphabet Inc. (Alphabet) became the successor issuer to Google. We generate revenues primarily by delivering relevant, cost-effective online advertising.
Basis of Consolidation	Basis of ConsolidationThe consolidated financial statements of Alphabet include the accounts of Alphabet and entities consolidated under the variable interest and voting models. Noncontrolling interests are not presented separately as the amounts are not material. All intercompany balances and transactions have been eliminated.
Unaudited Interim Financial Information	Unaudited Interim Financial Information The Consolidated Balance Sheet as of March 31, 2019, the Consolidated Statements of Income for the three months ended March 31, 2018 and 2019, the Consolidated Statements of Comprehensive Income for the three months ended March 31, 2018 and 2019, the Consolidated Statements of Stockholders' Equity for the three months ended March 31, 2018 and 2019 and the Consolidated Statements of Cash Flows for the three months ended March 31, 2018 and 2019 are unaudited. These unaudited interim consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States (GAAP). In our opinion, the unaudited interim consolidated financial statements include all adjustments of a normal recurring nature necessary for the fair presentation of our financial position as of March 31, 2019, our results of operations for the three months ended March 31, 2018 and 2019, and our cash flows for the three months ended March 31, 2018 and 2019. The results of operations for the three months ended March 31, 2019 are not necessarily indicative of the results to be expected for the year ending December 31, 2019. These unaudited interim consolidated financial statements should be read in conjunction with the consolidated financial statements and the related notes included in our Annual Report on Form 10-K for the fiscal year ended December 31, 2018, as amended, filed with the SEC.
Use of Estimates	Use of EstimatesPreparation of consolidated financial statements in conformity with GAAP requires us to make estimates and assumptions that affect the amounts reported and disclosed in the financial statements and the accompanying notes. Actual results could differ materially from these estimates. On an ongoing basis, we evaluate our estimates, including those related to bad debt allowance, sales allowances, fair values of financial instruments, intangible assets and goodwill, useful lives of intangible assets and property and equipment, income taxes, and contingent liabilities, among others. We base our estimates on assumptions, both historical and forward looking, that are believed to be reasonable, the results of which form the basis for making judgments about the carrying values of assets and liabilities.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Recently issued accounting pronouncements not yet adopted In June 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update No. 2016-13 (ASU 2016-13) "Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments" which requires the measurement and recognition of expected credit losses for financial assets held at amortized cost. ASU 2016-13 replaces the existing incurred loss impairment model with an expected loss model which requires the use of forward-looking information to calculate credit loss estimates. It also eliminates the concept of other-than-temporary impairment and requires credit losses related to available-for-sale debt securities to be recorded through an allowance for credit losses rather than as a reduction in the amortized cost basis of the securities. These changes will result in earlier recognition of credit losses. We will adopt ASU 2016-13 effective January 1, 2020 with the cumulative effect of adoption recorded as an adjustment to retained earnings. We are currently evaluating new credit loss models and updating our processes and controls in preparation for the adoption of ASU 2016-13. The effect on our consolidated financial statements will largely depend on the composition and credit quality of our investment portfolio and the economic conditions at the time of adoption. Recently adopted accounting pronouncements In February 2016, the FASB issued Accounting Standards Update No. 2016-02 (Topic 842) "Leases." Topic 842 supersedes the lease requirements in Accounting Standards Codification Topic 840, "Leases." Under Topic 842, lessees are required to recognize assets and liabilities on the balance sheet for most leases and provide enhanced disclosures. Leases will continue to be classified as either finance or operating. We adopted Topic 842 effective January 1, 2019. The most significant effects of Topic 842 were the recognition of $8.0 billion of operating lease assets and $8.4 billion of operating lease liabilities and the de-recognition of $1.5 billion of build-to-suit assets and liabilities. We applied Topic 842 to all leases as of January 1, 2019 with comparative periods continuing to be reported under Topic 840. In the adoption of Topic 842, we carried forward the assessment from Topic 840 of whether our contracts contain or are leases, the classification of our leases, and remaining lease terms. Our accounting for finance leases remains substantially unchanged. The standard does not have a significant effect on our consolidated results of operations or cash flows. See Note 4 for further details.
Prior Period Reclassifications	Prior Period ReclassificationsCertain amounts in prior periods have been reclassified to conform with current period presentation. Performance fees have been reclassified for all periods from general and administrative expenses to other income (expense), net to align with the presentation of the investment gains and losses on which the performance fees are based. See Note 13 for further details.
Revenue Recognition	Deferred Revenues We record deferred revenues when cash payments are received or due in advance of our performance, including amounts which are refundable.
Fair Value of Financial Instruments	Debt SecuritiesWe classify our marketable debt securities within Level 2 in the fair value hierarchy because we use quoted market prices to the extent available or alternative pricing sources and models utilizing market observable inputs to determine fair value. Equity Investments The following discusses our marketable equity securities, non-marketable equity securities, gains and losses on marketable and non-marketable equity securities, as well as our equity securities accounted for under the equity method. Marketable equity securities Our marketable equity securities are publicly traded stocks or funds measured at fair value and classified within Level 1 and 2 in the fair value hierarchy because we use quoted prices for identical assets in active markets or inputs that are based upon quoted prices for similar instruments in active markets.
Segment Reporting	We operate our business in multiple operating segments. Google is our only reportable segment. None of our other segments meet the quantitative thresholds to qualify as reportable segments; therefore, the other operating segments are combined and disclosed as Other Bets.

Nature of Operations and Summary of Significant Accounting Policies (Policies)

3 Months Ended

Mar. 31, 2019

Google was incorporated in California in September 1998 and re-incorporated in the State of Delaware in August 2003. In 2015, we implemented a holding company reorganization, and as a result, Alphabet Inc. (Alphabet) became the successor issuer to Google.

We generate revenues primarily by delivering relevant, cost-effective online advertising.

Basis of Consolidation

Basis of ConsolidationThe consolidated financial statements of Alphabet include the accounts of Alphabet and entities consolidated under the variable interest and voting models. Noncontrolling interests are not presented separately as the amounts are not material. All intercompany balances and transactions have been eliminated.

Unaudited Interim Financial Information

The Consolidated Balance Sheet as of March 31, 2019, the Consolidated Statements of Income for the three months ended March 31, 2018 and 2019, the Consolidated Statements of Comprehensive Income for the three months ended March 31, 2018 and 2019, the Consolidated Statements of Stockholders' Equity for the three months ended March 31, 2018 and 2019 and the Consolidated Statements of Cash Flows for the three months ended March 31, 2018 and 2019 are unaudited. These unaudited interim consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States (GAAP). In our opinion, the unaudited interim consolidated financial statements include all adjustments of a normal recurring nature necessary for the fair presentation of our financial position as of March 31, 2019, our results of operations for the three months ended March 31, 2018 and 2019, and our cash flows for the three months ended March 31, 2018 and 2019. The results of operations for the three months ended March 31, 2019 are not necessarily indicative of the results to be expected for the year ending December 31, 2019.

These unaudited interim consolidated financial statements should be read in conjunction with the consolidated financial statements and the related notes included in our Annual Report on Form 10-K for the fiscal year ended December 31, 2018, as amended, filed with the SEC.

Use of Estimates

Use of EstimatesPreparation of consolidated financial statements in conformity with GAAP requires us to make estimates and assumptions that affect the amounts reported and disclosed in the financial statements and the accompanying notes. Actual results could differ materially from these estimates. On an ongoing basis, we evaluate our estimates, including those related to bad debt allowance, sales allowances, fair values of financial instruments, intangible assets and goodwill, useful lives of intangible assets and property and equipment, income taxes, and contingent liabilities, among others. We base our estimates on assumptions, both historical and forward looking, that are believed to be reasonable, the results of which form the basis for making judgments about the carrying values of assets and liabilities.

Recent Accounting Pronouncements

Recently issued accounting pronouncements not yet adopted

In June 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update No. 2016-13 (ASU 2016-13) "Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments" which requires the measurement and recognition of expected credit losses for financial assets held at amortized cost. ASU 2016-13 replaces the existing incurred loss impairment model with an expected loss model which requires the use of forward-looking information to calculate credit loss estimates. It also eliminates the concept of other-than-temporary impairment and requires credit losses related to available-for-sale debt securities to be recorded through an allowance for credit losses rather than as a reduction in the amortized cost basis of the securities. These changes will result in earlier recognition of credit losses. We will adopt ASU 2016-13 effective January 1, 2020 with the cumulative effect of adoption recorded as an adjustment to retained earnings. We are currently evaluating new credit loss models and updating our processes and controls in preparation for the adoption of ASU 2016-13. The effect on our consolidated financial statements will largely depend on the composition and credit quality of our investment portfolio and the economic conditions at the time of adoption.

Recently adopted accounting pronouncements

In February 2016, the FASB issued Accounting Standards Update No. 2016-02 (Topic 842) "Leases." Topic 842 supersedes the lease requirements in Accounting Standards Codification Topic 840, "Leases." Under Topic 842, lessees are required to recognize assets and liabilities on the balance sheet for most leases and provide enhanced disclosures. Leases will continue to be classified as either finance or operating.

We adopted Topic 842 effective January 1, 2019. The most significant effects of Topic 842 were the recognition of $8.0 billion of operating lease assets and $8.4 billion of operating lease liabilities and the de-recognition of $1.5 billion of build-to-suit assets and liabilities. We applied Topic 842 to all leases as of January 1, 2019 with comparative periods continuing to be reported under Topic 840. In the adoption of Topic 842, we carried forward the assessment from Topic 840 of whether our contracts contain or are leases, the classification of our leases, and remaining lease terms. Our accounting for finance leases remains substantially unchanged. The standard does not have a significant effect on our consolidated results of operations or cash flows. See Note 4 for further details.

Prior Period Reclassifications

Prior Period ReclassificationsCertain amounts in prior periods have been reclassified to conform with current period presentation. Performance fees have been reclassified for all periods from general and administrative expenses to other income (expense), net to align with the presentation of the investment gains and losses on which the performance fees are based. See Note 13 for further details.

Revenue Recognition

Deferred Revenues

We record deferred revenues when cash payments are received or due in advance of our performance, including amounts which are refundable.

Fair Value of Financial Instruments

Debt SecuritiesWe classify our marketable debt securities within Level 2 in the fair value hierarchy because we use quoted market prices to the extent available or alternative pricing sources and models utilizing market observable inputs to determine fair value. Equity Investments

The following discusses our marketable equity securities, non-marketable equity securities, gains and losses on marketable and non-marketable equity securities, as well as our equity securities accounted for under the equity method.

Marketable equity securities

Our marketable equity securities are publicly traded stocks or funds measured at fair value and classified within Level 1 and 2 in the fair value hierarchy because we use quoted prices for identical assets in active markets or inputs that are based upon quoted prices for similar instruments in active markets.

Segment Reporting

We operate our business in multiple operating segments. Google is our only reportable segment. None of our other segments meet the quantitative thresholds to qualify as reportable segments; therefore, the other operating segments are combined and disclosed as Other Bets.