Debt and Credit Facilities - Summary of Debt Carrying Amount (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Short-term and long-term debt	$ 24,102	$ 24,593
Less: current portion	2,999	2,499
Total long-term debt, net	$ 21,103	22,094
Unsecured Debt \| Senior Unsecured Notes Due In February 2020
Debt Instrument [Line Items]
Interest Rate	2.35%
Long-term debt	$ 0	500
Unsecured Debt \| Senior Unsecured Notes Due in September 2020
Debt Instrument [Line Items]
Interest Rate	2.55%
Long-term debt	$ 2,000	1,999
Unsecured Debt \| Senior Unsecured Notes Due in April 2021
Debt Instrument [Line Items]
Interest Rate	4.50%
Long-term debt	$ 999	998
Unsecured Debt \| Senior Unsecured Notes Due In December 2021
Debt Instrument [Line Items]
Interest Rate	4.40%
Long-term debt	$ 1,249	1,248
Unsecured Debt \| Senior Unsecured Notes Due in March 2022
Debt Instrument [Line Items]
Interest Rate	1.95%
Long-term debt	$ 499	499
Unsecured Debt \| Senior Unsecured Notes Due in September 2022
Debt Instrument [Line Items]
Interest Rate	3.25%
Long-term debt	$ 998	998
Unsecured Debt \| Senior Unsecured Notes Due in September 2023
Debt Instrument [Line Items]
Interest Rate	2.50%
Long-term debt	$ 747	747
Unsecured Debt \| Senior Unsecured Notes Due in April 2024
Debt Instrument [Line Items]
Interest Rate	3.70%
Long-term debt	$ 1,745	1,745
Unsecured Debt \| Senior Unsecured Notes Due in February 2025
Debt Instrument [Line Items]
Interest Rate	3.50%
Long-term debt	$ 1,746	1,746
Unsecured Debt \| Senior Unsecured Notes Due in March 2026
Debt Instrument [Line Items]
Interest Rate	3.65%
Long-term debt	$ 2,735	2,734
Unsecured Debt \| Senior Unsecured Notes Due in March 2027
Debt Instrument [Line Items]
Interest Rate	2.95%
Long-term debt	$ 1,246	1,245
Unsecured Debt \| Senior Unsecured Notes Due in September 2035
Debt Instrument [Line Items]
Interest Rate	4.60%
Long-term debt	$ 991	991
Unsecured Debt \| Senior Unsecured Notes Due in September 2036
Debt Instrument [Line Items]
Interest Rate	4.00%
Long-term debt	$ 741	741
Unsecured Debt \| Senior Unsecured Notes Due in December 2041
Debt Instrument [Line Items]
Interest Rate	5.65%
Long-term debt	$ 996	995
Unsecured Debt \| Senior Unsecured Notes Due in April 2044
Debt Instrument [Line Items]
Interest Rate	4.80%
Long-term debt	$ 1,734	1,734
Unsecured Debt \| Senior Unsecured Notes Due in February 2045
Debt Instrument [Line Items]
Interest Rate	4.50%
Long-term debt	$ 1,732	1,731
Unsecured Debt \| Senior Unsecured Notes Due in March 2046
Debt Instrument [Line Items]
Interest Rate	4.75%
Long-term debt	$ 2,218	2,217
Unsecured Debt \| Senior Unsecured Notes Due in March 2047
Debt Instrument [Line Items]
Interest Rate	4.15%
Long-term debt	$ 1,726	$ 1,725

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
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Contractual interest rate for funds borrowed, under the debt agreement.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(3)
-URI http://asc.fasb.org/extlink&oid=109500613&loc=SL6031897-161870

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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