Long-Term Debt (Details 1) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Long-Term Debt (Table Amounts) [Abstract]
Long-term debt	$ 15,266
Other long-term debt	271	$ 273
Debt issuance costs	(82)	(31)
Total long-term debt	15,266	7,070
Less: current portion	867	12
Long-term debt, net of current portion	$ 14,399	7,058
2018
Long-Term Debt (Table Amounts) [Abstract]
Debt Instrument, Interest Rate, Stated Percentage	1.75%
Long-term debt	$ 850	850
2019
Long-Term Debt (Table Amounts) [Abstract]
Debt Instrument, Interest Rate, Stated Percentage	5.05%
Long-term debt	$ 500	500
2020
Long-Term Debt (Table Amounts) [Abstract]
Debt Instrument, Interest Rate, Stated Percentage	2.08%
Long-term debt	$ 1,000	0
2021
Long-Term Debt (Table Amounts) [Abstract]
Debt Instrument, Interest Rate, Stated Percentage	3.50%
Long-term debt	$ 700	700
2022
Long-Term Debt (Table Amounts) [Abstract]
Debt Instrument, Interest Rate, Stated Percentage	2.55%
Long-term debt	$ 1,500	0
2023
Long-Term Debt (Table Amounts) [Abstract]
Debt Instrument, Interest Rate, Stated Percentage	3.25%
Long-term debt	$ 1,050	1,050
2025
Long-Term Debt (Table Amounts) [Abstract]
Debt Instrument, Interest Rate, Stated Percentage	2.93%
Long-term debt	$ 1,500	0
2026
Long-Term Debt (Table Amounts) [Abstract]
Long-term debt	$ 527	527
2027
Long-Term Debt (Table Amounts) [Abstract]
Debt Instrument, Interest Rate, Stated Percentage	3.20%
Long-term debt	$ 750	750
2028
Long-Term Debt (Table Amounts) [Abstract]
Debt Instrument, Interest Rate, Stated Percentage	3.25%
Long-term debt	$ 2,000	0
2031
Long-Term Debt (Table Amounts) [Abstract]
Debt Instrument, Interest Rate, Stated Percentage	7.75%
Long-term debt	$ 466	466
2040
Long-Term Debt (Table Amounts) [Abstract]
Debt Instrument, Interest Rate, Stated Percentage	5.05%
Long-term debt	$ 300	300
2043
Long-Term Debt (Table Amounts) [Abstract]
Debt Instrument, Interest Rate, Stated Percentage	4.75%
Long-term debt	$ 950	950
2045
Long-Term Debt (Table Amounts) [Abstract]
Debt Instrument, Interest Rate, Stated Percentage	3.85%
Long-term debt	$ 600	600
2047
Long-Term Debt (Table Amounts) [Abstract]
Debt Instrument, Interest Rate, Stated Percentage	4.03%
Long-term debt	$ 2,250	0
Two Year Term [Member] [Domain]
Long-Term Debt (Table Amounts) [Abstract]
Debt Instrument, Interest Rate, Stated Percentage	1.62%
Credit facilities	$ 134	$ 135
Minimum \| 2026
Long-Term Debt (Table Amounts) [Abstract]
Debt Instrument, Interest Rate, Stated Percentage	7.75%
Maximum \| 2026
Long-Term Debt (Table Amounts) [Abstract]
Debt Instrument, Interest Rate, Stated Percentage	7.88%

Sum of the carrying values as of the balance sheet date of all debt, including all short-term borrowings, long-term debt, and capital lease obligations.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 210
-Section S99
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Contractual interest rate for funds borrowed, under the debt agreement.

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Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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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.

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Amount of long-term debt and capital lease obligation due after one year or beyond the normal operating cycle, if longer.

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Amount of long-term debt and capital leases due within one year or the normal operating cycle, if longer.

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Amount of long-term debt classified as other.

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