Income Taxes - Additional Information Regarding Examinations (Detail) - USD ($) $ in Billions |
3 Months Ended | 12 Months Ended | |||
|---|---|---|---|---|---|
Sep. 30, 2021 |
Dec. 31, 2020 |
Jun. 30, 2018 |
Jun. 30, 2016 |
Jun. 30, 2011 |
|
| Earliest Tax Year | Foreign Country | |||||
| Income Tax Examination [Line Items] | |||||
| Tax years subject to examination | 1996 | ||||
| Latest Tax Year | Foreign Country | |||||
| Income Tax Examination [Line Items] | |||||
| Tax years subject to examination | 2021 | ||||
| Internal Revenue Service (IRS) | |||||
| Income Tax Examination [Line Items] | |||||
| Settlement payments including tax and interest | $ 1.7 | ||||
| Internal Revenue Service (IRS) | Earliest Tax Year | |||||
| Income Tax Examination [Line Items] | |||||
| Tax years under audit | 2004 | 2010 | 2007 | 2004 | |
| Tax years subject to examination | 2004 | ||||
| Internal Revenue Service (IRS) | Latest Tax Year | |||||
| Income Tax Examination [Line Items] | |||||
| Tax years under audit | 2013 | 2013 | 2009 | 2006 | |
| Tax years subject to examination | 2017 | ||||