Income Taxes (Details) - USD ($) $ in Millions |
3 Months Ended | 9 Months Ended | |||
---|---|---|---|---|---|
Feb. 18, 2014 |
Sep. 30, 2018 |
Sep. 30, 2017 |
Sep. 30, 2018 |
Sep. 30, 2017 |
|
Income Tax Examination [Line Items] | |||||
Effective income tax rate reconciliation, percent | 23.70% | 29.30% | 24.10% | 28.70% | |
Discrete tax expense (benefit) | $ (37) | ||||
Effective income tax rate reconciliation, tax credit, foreign, amount | 22 | ||||
Effective income tax rate reconciliation, share-based compensation, excess tax benefit, amount | $ 6 | $ 32 | |||
Potential decrease in unrecognized tax benefits | $ 30 | $ 30 | |||
Internal Revenue Service (IRS) | Tax Year 2006 | |||||
Income Tax Examination [Line Items] | |||||
IRS Notice of Deficiency tax assessment | $ 70 |