Fair Value Measurements (Details 1) - USD ($)	Sep. 30, 2020	Apr. 30, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Notes payable, carrying value	$ 7,425,000,000.0		$ 5,954,800,000
Debt instruments, fair value	8,336,000,000.0		6,553,600,000
2.900% Senior Notes due 2020
Debt Instrument [Line Items]
Notes payable, fair value	0		1,509,600,000
Notes payable, carrying value	$ 0		1,495,800,000
Senior notes interest rate	2.90%
3.625% Senior Notes due 2022
Debt Instrument [Line Items]
Notes payable, fair value	$ 1,058,400,000		1,038,900,000
Notes payable, carrying value	$ 997,500,000		996,600,000
Senior notes interest rate	3.625%
4.050% Senior Notes due 2025
Debt Instrument [Line Items]
Notes payable, fair value	$ 1,988,500,000		1,897,200,000
Notes payable, carrying value	$ 1,740,700,000		1,739,500,000
Senior notes interest rate	4.05%
2.250% Senior Notes due May 1, 2030
Debt Instrument [Line Items]
Notes payable, fair value	$ 1,532,800,000		0
Notes payable, carrying value	$ 1,491,000,000.0		0
Senior notes interest rate	2.25%
5.200% Senior Notes due 2045
Debt Instrument [Line Items]
Notes payable, fair value	$ 2,286,300,000		2,107,900,000
Notes payable, carrying value	$ 1,723,300,000		1,722,900,000
Senior notes interest rate	5.20%
3.150% Senior Notes due May 1, 2050
Debt Instrument [Line Items]
Notes payable, fair value	$ 1,470,000,000.0		0
Notes payable, carrying value	$ 1,472,500,000		$ 0
Senior notes interest rate	3.15%
Senior Notes
Debt Instrument [Line Items]
Face amount		$ 3,000,000,000.0
Senior Notes | 2.250% Senior Notes due May 1, 2030
Debt Instrument [Line Items]
Senior notes interest rate		2.25%
Face amount		$ 1,500,000,000
Senior Notes | 3.150% Senior Notes due May 1, 2050
Debt Instrument [Line Items]
Senior notes interest rate		3.15%
Face amount		$ 1,500,000,000