Debt - Summary of Debt (Detail) - USD ($)		Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022	Mar. 31, 2020	Oct. 31, 2018	Mar. 31, 2018	Apr. 30, 2017	Aug. 31, 2016	Jan. 31, 2015	Apr. 30, 2014	Nov. 30, 2002	Mar. 31, 1999
Debt Instrument [Line Items]
Debt, Long-term and Short-term, Combined Amount	[1]	$ 6,389,300,000	$ 6,388,300,000	$ 6,385,600,000
Fair Value		5,881,000,000	5,717,900,000	6,692,600,000
2.45% Senior Notes due 2027 (issued: $500.0, August 2016)
Debt Instrument [Line Items]
Long-term Debt		498,300,000	498,200,000	497,800,000
Fair Value		464,200,000	457,700,000	487,900,000
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		497,700,000	497,500,000	497,100,000
Fair Value		463,800,000	460,300,000	$ 489,400,000
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		297,600,000	297,500,000	297,300,000
Fair Value		329,600,000	326,800,000	358,800,000
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		546,500,000	546,400,000	546,100,000
Fair Value		538,500,000	527,800,000	573,500,000
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		497,000,000.0	496,900,000	496,600,000
Fair Value		460,000,000.0	448,600,000	496,200,000
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		496,000,000.0	495,900,000	495,600,000
Fair Value		446,900,000	438,100,000	$ 487,000,000.0
Debt, stated interest rate				3.00%
Debt, face amount				$ 500,000,000.0
6.25% Senior Notes due 2032 (issued: $400.0, November 2002)
Debt Instrument [Line Items]
Long-term Debt		396,500,000	396,400,000	396,200,000
Fair Value		448,100,000	435,400,000	494,800,000
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	346,900,000	346,800,000
Fair Value		312,300,000	298,400,000	368,700,000
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		395,800,000	395,700,000	395,700,000
Fair Value		324,000,000.0	310,200,000	386,000,000.0
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		842,100,000	842,100,000	841,900,000
Fair Value		743,800,000	716,200,000	894,500,000
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		590,400,000	590,400,000	590,300,000
Fair Value		530,000,000.0	507,000,000.0	637,400,000
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		491,000,000.0	490,900,000	490,800,000
Fair Value		420,300,000	404,900,000	514,900,000
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		493,500,000	493,500,000	493,400,000
Fair Value		$ 399,500,000	$ 386,500,000	$ 503,500,000
Debt, stated interest rate				3.70%
Debt, face amount				$ 500,000,000.0

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