Debt - Summary of Debt (Detail) - USD ($)		Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Jun. 30, 2021	Mar. 31, 2020	Oct. 31, 2018	Mar. 31, 2018	Apr. 30, 2017	Aug. 31, 2016	Jan. 31, 2015	Apr. 30, 2014	Aug. 31, 2011	Nov. 30, 2002	Mar. 31, 1999
Debt Instrument [Line Items]
Fair Value		$ 6,028,900,000		$ 5,857,400,000	$ 6,446,700,000
Debt, Long-term and Short-term, Combined Amount	[1]	6,386,500,000		4,898,800,000	5,397,500,000
3.75% Senior Notes due 2021 (issued: $500.0, August 2011)
Debt Instrument [Line Items]
Long-term Debt		0		0	499,900,000
Fair Value		0		0	502,500,000
Debt, stated interest rate													3.75%
Debt, face amount													$ 500,000,000.0
2.45% Senior Notes due 2027 (issued: $500.0, August 2016)
Debt Instrument [Line Items]
Long-term Debt		497,900,000		497,700,000	497,500,000
Fair Value		471,300,000		517,900,000	529,900,000
Debt, stated interest rate										2.45%
Debt, face amount										$ 500,000,000.0
2.50% Senior Notes due 2027 (issued: $500.0, March 2022)
Debt Instrument [Line Items]
Long-term Debt		497,200,000		0	0
Fair Value		472,600,000		0	0
Debt, stated interest rate			2.50%
Debt, face amount			$ 500,000,000.0
6 5/8% Senior Notes due 2029 (issued: $300.0, March 1999)
Debt Instrument [Line Items]
Long-term Debt		297,300,000		297,200,000	297,000,000.0
Fair Value		340,600,000		388,200,000	396,100,000
Debt, stated interest rate															6.625%
Debt, face amount															$ 300,000,000.0
4.00% Senior Notes due 2029 (issued: $550.0, October 2018)
Debt Instrument [Line Items]
Long-term Debt		546,200,000		545,900,000	545,700,000
Fair Value		543,300,000		621,000,000.0	631,500,000
Debt, stated interest rate							4.00%
Debt, face amount							$ 550,000,000.0
3.20% Senior Notes due 2030 (issued: $500.0, March 2020)
Debt Instrument [Line Items]
Long-term Debt		496,700,000		496,500,000	496,300,000
Fair Value		463,000,000.0		536,300,000	549,000,000.0
Debt, stated interest rate						3.20%
Debt, face amount						$ 500,000,000.0
3.00% Senior Notes due 2032 (issued: $500.0, March 2022)
Debt Instrument [Line Items]
Long-term Debt		495,700,000		0	0
Fair Value		448,300,000		0	0
Debt, stated interest rate			3.00%
Debt, face amount			$ 500,000,000
6.25% Senior Notes due 2032 (issued: $400.0, November 2002)
Debt Instrument [Line Items]
Long-term Debt		396,300,000		396,200,000	396,100,000
Fair Value		459,200,000		547,900,000	553,700,000
Debt, stated interest rate														6.25%
Debt, face amount														$ 400,000,000.0
4.35% Senior Notes due 2044 (issued: $350.0, April 2014)
Debt Instrument [Line Items]
Long-term Debt		346,900,000		346,800,000	346,800,000
Fair Value		324,600,000		428,400,000	434,800,000
Debt, stated interest rate												4.35%
Debt, face amount												$ 350,000,000.0
3.70% Senior Notes due 2045 (issued: $400.0, January 2015)
Debt Instrument [Line Items]
Long-term Debt		395,700,000		395,600,000	395,600,000
Fair Value		332,400,000		447,100,000	458,100,000
Debt, stated interest rate											3.70%
Debt, face amount											$ 400,000,000.0
4.125% Senior Notes due 2047 (issued: $850.0, April 2017)
Debt Instrument [Line Items]
Long-term Debt		842,000,000.0		841,900,000	841,800,000
Fair Value		769,300,000		1,029,300,000	1,041,400,000
Debt, stated interest rate									4.125%
Debt, face amount									$ 850,000,000.0
4.20% Senior Notes due 2048 (issued: $600.0, March 2018)
Debt Instrument [Line Items]
Long-term Debt		590,300,000		590,200,000	590,100,000
Fair Value		550,500,000		741,300,000	747,000,000.0
Debt, stated interest rate								4.20%
Debt, face amount								$ 600,000,000.0
3.95% Senior Notes due 2050 (issued: $500.0, March 2020)
Debt Instrument [Line Items]
Long-term Debt		490,900,000		490,800,000	490,700,000
Fair Value		437,800,000		600,000,000.0	602,700,000
Debt, stated interest rate						3.95%
Debt, face amount						$ 500,000,000.0
3.70% Senior Notes due 2052 (issued: $500.0, March 2022)
Debt Instrument [Line Items]
Long-term Debt		493,400,000		0	0
Fair Value		$ 416,000,000.0		$ 0	$ 0
Debt, stated interest rate			3.70%
Debt, face amount			$ 500,000,000

[1] Consists of long-term debt. See Note 4 – Debt for further discussion.