Long-Term Debt - (Schedule of Long-Term Debt) (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2018	Dec. 31, 2017
Long-Term Debt
Other	$ (1)	$ 15
Long-term Debt	9,076	8,763
Current portion of long-term debt	(1,036)	(1,045)
Long-term debt, excluding current portion	8,040	7,718
Senior Notes due April 2018, interest payable semi-annually at 2.000%
Long-Term Debt
Senior notes	$ 250	250
Debt instrument, stated percentage	2.00%
Senior Notes due October 2018, interest payable semi-annually at 2.850%
Long-Term Debt
Senior notes	$ 750	750
Debt instrument, stated percentage	2.85%
Senior Notes due October 2020, interest payable semi-annually at 3.625%
Long-Term Debt
Senior notes	$ 1,150	1,150
Debt instrument, stated percentage	3.625%
Senior Euro Notes due January 2021, interest payable annually at 0.400%
Long-Term Debt
Senior notes	$ 616	599
Debt instrument, stated percentage	0.40%
Senior Notes due August 2021, interest payable semi-annually at 2.250%
Long-Term Debt
Senior notes	$ 750	750
Debt instrument, stated percentage	2.25%
Senior GBP Notes due June 2022, interest payable annually at 1.700%
Long-Term Debt
Senior notes	$ 420	405
Debt instrument, stated percentage	1.70%
Senior Notes due October 2022, interest payable semi-annually at 4.500%
Long-Term Debt
Senior notes	$ 300	300
Debt instrument, stated percentage	4.50%
Senior Notes due April 2023, interest payable semi-annually at 3.500%
Long-Term Debt
Senior notes	$ 700	700
Debt instrument, stated percentage	3.50%
Senior Notes due June 2024, interest payable semi-annually at 3.875%
Long-Term Debt
Senior notes	$ 400	400
Debt instrument, stated percentage	3.875%
Senior Euro Notes due July 2024, interest payable annually at 1.100%
Long-Term Debt
Senior notes	$ 616	599
Debt instrument, stated percentage	1.10%
Senior Notes due October 2025, interest payable semi-annually at 5.000%
Long-Term Debt
Senior notes	$ 900	900
Debt instrument, stated percentage	5.00%
Senior Notes due August 2026, interest payable semi-annually at 3.000%
Long-Term Debt
Senior notes	$ 1,250	1,250
Debt instrument, stated percentage	3.00%
Senior Notes due August 2046, interest payable semi-annually at 4.500%
Long-Term Debt
Senior notes	$ 500	500
Debt instrument, stated percentage	4.50%
Revolving loan
Long-Term Debt
Loans	$ 475	$ 195
Unused commitment fee	0.25%
Weighted average interest rate	2.73%
One month LIBOR \| Maximum \| Revolving loan
Long-Term Debt
Applicable margin	1.75%

Debt Instrument, Unamortized (Discount) Premium, Debt Issuance Costs, and Capital Lease Obligations, Net

No definition available.

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- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

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- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

The fee, expressed as a percentage of the line of credit facility, for available but unused credit capacity under the credit facility.

+ References

No definition available.

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- Definition

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/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
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- Definition

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.

+ References

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Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

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- Definition

Weighted average interest rate of long-term debt outstanding calculated at point in time.

+ References

No definition available.

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- Definition

Carrying value as of the balance sheet date, including the current and noncurrent portions, of collateralized debt obligations (with maturities initially due after one year or beyond the operating cycle, if longer). Such obligations include mortgage loans, chattel loans, and any other borrowings secured by assets of the borrower.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
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- Definition

Including the current and noncurrent portions, carrying value as of the balance sheet date of Notes with the highest claim on the assets of the issuer in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle if longer). Senior note holders are paid off in full before any payments are made to junior note holders.

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