Debt (Narrative) (Details)	1 Months Ended					12 Months Ended
	Feb. 28, 2022 USD ($) renewal_option	Dec. 31, 2021 USD ($)	Oct. 31, 2020 USD ($) renewal_option	Apr. 30, 2020 USD ($) renewal_option	Mar. 31, 2020 USD ($)	Jan. 29, 2022 USD ($) renewal_option note	Jan. 30, 2021 USD ($) note	Feb. 01, 2020 USD ($)	Jan. 31, 2022 USD ($)	Dec. 13, 2021	Oct. 30, 2021 USD ($)	May 31, 2020 USD ($)
Debt Instrument [Line Items]
Loss on early extinguishment of debt						$ 0	$ 239,953,000	$ 0
Collateral trust						56,700,000	56,100,000
Senior Notes
Debt Instrument [Line Items]
Aggregate principal amount of unsecured senior notes				$ 2,000,000,000							$ 1,000,000,000
Number of tenors | renewal_option			2	4
Proceeds from debt issuance, net of discounts and other issuance costs			$ 987,200,000	$ 1,973,000,000
Cash tender offer, principal amount, accepted for purchase			775,000,000
Payment for cash tender offer, principal amount			1,003,000,000.000
Loss on early extinguishment of debt			240,000,000
Unamortized discount and debt issuance costs						$ 22,700,000	$ 26,900,000
Number of series notes | note						7	8
Senior Notes | Level 1
Debt Instrument [Line Items]
Unsecured senior notes estimated fair value						$ 2,600,000,000	$ 2,800,000,000
Unsecured Revolving Credit Facility
Debt Instrument [Line Items]
Maximum borrowing capacity for revolving credit facility						800,000,000						$ 800,000,000
Sublimit for issuance of standby letters of credit						300,000,000
Option to increase credit facility, additional amount (up to)						$ 300,000,000
Number of renewal options (up to) | renewal_option						2
Renewal option, term						1 year
Amount borrowed from revolving credit facility					$ 800,000,000
Interest rate, margin in addition to LIBOR (percent)					0.875%
Current interest rate for revolving credit facility borrowings (percent)					1.76%
Repayment of revolving credit facility			800,000,000
Amount outstanding under the revolving credit facility						$ 0
Current borrowing capacity						800,000,000
Unsecured Revolving Credit Facility | Subsequent Event
Debt Instrument [Line Items]
Maximum borrowing capacity for revolving credit facility									$ 800,000,000
Senior Revolving Credit Facility
Debt Instrument [Line Items]
Maximum borrowing capacity for revolving credit facility												$ 500,000,000
Amount outstanding under the revolving credit facility			0
Senior Unsecured Revolving Credit Facility | Subsequent Event
Debt Instrument [Line Items]
Maximum borrowing capacity for revolving credit facility	$ 1,300,000,000
Option to increase credit facility, additional amount (up to)	$ 700,000,000
Number of renewal options (up to) | renewal_option	2
Renewal option, term	1 year
Senior Unsecured Revolving Credit Facility | Subsequent Event | Standby Letters of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity for revolving credit facility	$ 300,000,000
Standby Letters of Credit
Debt Instrument [Line Items]
Amount outstanding under the revolving credit facility						0
Letters of credit, outstanding						3,300,000	15,300,000
Trade Letters of Credit
Debt Instrument [Line Items]
Letters of credit, outstanding						$ 19,300,000	$ 16,300,000
4.600% Senior Notes due 2025 | Senior Notes
Debt Instrument [Line Items]
Aggregate principal amount of unsecured senior notes				$ 700,000,000
Unsecured senior notes interest rate (percent)				4.60%		4.60%
4.700% Senior Notes due 2027 | Senior Notes
Debt Instrument [Line Items]
Aggregate principal amount of unsecured senior notes				$ 400,000,000
Unsecured senior notes interest rate (percent)				4.70%		4.70%
Cash tender offer, principal amount, accepted for purchase			158,000,000
4.800% Senior Notes due 2030 | Senior Notes
Debt Instrument [Line Items]
Aggregate principal amount of unsecured senior notes				$ 400,000,000
Unsecured senior notes interest rate (percent)				4.80%		4.80%
Cash tender offer, principal amount, accepted for purchase			266,000,000
5.450% Senior Notes due 2050 | Senior Notes
Debt Instrument [Line Items]
Aggregate principal amount of unsecured senior notes				$ 500,000,000
Unsecured senior notes interest rate (percent)				5.45%		5.45%
Cash tender offer, principal amount, accepted for purchase			$ 351,000,000
0.875% Senior Notes due 2026 | Senior Notes
Debt Instrument [Line Items]
Aggregate principal amount of unsecured senior notes											$ 500,000,000
Unsecured senior notes interest rate (percent)						0.875%					0.875%
1.875% Senior Notes due 2031 | Senior Notes
Debt Instrument [Line Items]
Aggregate principal amount of unsecured senior notes											$ 500,000,000
Unsecured senior notes interest rate (percent)						1.875%					1.875%
6.530% Series B Senior Notes due 2021 | Series B Unsecured Senior Notes
Debt Instrument [Line Items]
Unsecured senior notes interest rate (percent)						6.53%				6.53%
Extinguishment of debt		$ 65,000,000
3.375% Senior Notes due 2024 | Senior Notes
Debt Instrument [Line Items]
Aggregate principal amount of unsecured senior notes						$ 250,000,000
Unsecured senior notes interest rate (percent)						3.375%