Indebtedness - Principal Payments Due on Long-Term Borrowings (Detail) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
2021 (After September 30,)	$ 0
2022	500
2023	500
2024	500
2025	700
Thereafter	5,348
Total principal payment	7,548	$ 6,430
4.50% 2012 Senior Notes, due 2022
Debt Instrument [Line Items]
2022	500
Total principal payment	$ 500	$ 500
Debt Instrument, Interest Rate, Stated Percentage	4.50%	4.50%
4.875% 2013 Senior Notes, due 2024
Debt Instrument [Line Items]
2024	$ 500
Total principal payment	$ 500	$ 500
Debt Instrument, Interest Rate, Stated Percentage	4.875%	4.875%
5.25% 2014 Senior Notes, due 2044
Debt Instrument [Line Items]
Thereafter	$ 600
Total principal payment	$ 600	$ 600
Debt Instrument, Interest Rate, Stated Percentage	5.25%	5.25%
1.75% 2015 Senior Notes, due 2027
Debt Instrument [Line Items]
Thereafter	$ 579
Total principal payment	$ 579	$ 612
Debt Instrument, Interest Rate, Stated Percentage	1.75%	1.75%
2.625% 2017 Senior Notes, due 2023
Debt Instrument [Line Items]
2023	$ 500
Total principal payment	$ 500	$ 500
Debt Instrument, Interest Rate, Stated Percentage	2.625%	2.625%
3.25% 2017 Senior Notes, due 2028
Debt Instrument [Line Items]
Thereafter	$ 500
Total principal payment	$ 500	$ 500
Debt Instrument, Interest Rate, Stated Percentage	3.25%	3.25%
4.25% 2018 Senior Notes, due 2029
Debt Instrument [Line Items]
Thereafter	$ 400
Total principal payment	$ 400	$ 400
Debt Instrument, Interest Rate, Stated Percentage	4.25%	4.25%
4.875% 2018 Senior Notes, due 2048
Debt Instrument [Line Items]
Thereafter	$ 400
Total principal payment	$ 400	$ 400
Debt Instrument, Interest Rate, Stated Percentage	4.875%	4.875%
0.950% Senior Notes Due 2030
Debt Instrument [Line Items]
Thereafter	$ 869
Total principal payment	$ 869	$ 918
Debt Instrument, Interest Rate, Stated Percentage	0.95%	0.95%
3.75% 2020 Senior Notes, due 2025
Debt Instrument [Line Items]
2025	$ 700
Total principal payment	$ 700	$ 700
Debt Instrument, Interest Rate, Stated Percentage	3.75%	3.75%
3.25% 2020 Senior Notes, due 2050
Debt Instrument [Line Items]
Thereafter	$ 300
Total principal payment	$ 300	$ 300
Debt Instrument, Interest Rate, Stated Percentage	3.25%	3.25%
2.55% 2020 Senior Notes, due 2060
Debt Instrument [Line Items]
Thereafter	$ 500
Total principal payment	$ 500	$ 500
Debt Instrument, Interest Rate, Stated Percentage	2.55%	2.55%
2.00% 2021 Senior Note, due 2031
Debt Instrument [Line Items]
Thereafter	$ 600
Total principal payment	$ 600
Debt Instrument, Interest Rate, Stated Percentage	2.00%
2.75% 2021 Senior Note, due 2041
Debt Instrument [Line Items]
Thereafter	$ 600
Total principal payment	$ 600
Debt Instrument, Interest Rate, Stated Percentage	2.75%

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Contractual interest rate for funds borrowed, under the debt agreement.

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