Fair Value of Financial Instruments (Details) - Senior Notes - Fair Value, Inputs, Level 2	Jun. 30, 2021 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed rate senior notes carrying amount	$ 8,000,000,000
$500 2.800% senior notes due 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Face amount of debt	$ 500,000,000
Fixed interest rate (as a percent)	2.80%
Long-term debt, fair value	$ 505,000,000
$500 3.125% senior notes due 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Face amount of debt	$ 500,000,000
Fixed interest rate (as a percent)	3.125%
Long-term debt, fair value	$ 515,000,000
$300 0.450% senior notes due 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Face amount of debt	$ 300,000,000
Fixed interest rate (as a percent)	0.45%
Long-term debt, fair value	$ 300,000,000
$700 3.650% senior notes due 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Face amount of debt	$ 700,000,000
Fixed interest rate (as a percent)	3.65%
Long-term debt, fair value	$ 747,000,000
$500 2.350% senior notes due 2024
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Face amount of debt	$ 500,000,000
Fixed interest rate (as a percent)	2.35%
Long-term debt, fair value	$ 524,000,000
$300 3.850% senior notes due 2025
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Face amount of debt	$ 300,000,000
Fixed interest rate (as a percent)	3.85%
Long-term debt, fair value	$ 333,000,000
$700 1.000% senior notes due 2025
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Face amount of debt	$ 700,000,000
Fixed interest rate (as a percent)	1.00%
Long-term debt, fair value	$ 695,000,000
$700 3.800% senior notes due 2026
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Face amount of debt	$ 700,000,000
Fixed interest rate (as a percent)	3.80%
Long-term debt, fair value	$ 782,000,000
$700 1.400% senior notes due 2027
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Face amount of debt	$ 700,000,000
Fixed interest rate (as a percent)	1.40%
Long-term debt, fair value	$ 689,000,000
$800 4.200% senior notes due 2028
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Face amount of debt	$ 800,000,000
Fixed interest rate (as a percent)	4.20%
Long-term debt, fair value	$ 920,000,000
$700 2.950% senior notes due 2029
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Face amount of debt	$ 700,000,000
Fixed interest rate (as a percent)	2.95%
Long-term debt, fair value	$ 748,000,000
$600 2.000% senior notes due 2030
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Face amount of debt	$ 600,000,000
Fixed interest rate (as a percent)	2.00%
Long-term debt, fair value	$ 591,000,000
$1,000 1.750% senior notes due 2031
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Face amount of debt	$ 1,000,000,000
Fixed interest rate (as a percent)	1.75%
Long-term debt, fair value	$ 960,000,000