Debt and Other Obligations Contractual Maturities (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Contractual Maturities [Abstract]
Long-term Debt, Maturities, Repayments of Principal, Remainder of Fiscal Year	$ 87
Long-term Debt, Maturities, Repayments of Principal in Year Two	168
Long-term Debt, Maturities, Repayments of Principal in Year Three	156
Long-term Debt, Maturities, Repayments of Principal in Year Four	1,826
Long-term Debt, Maturities, Repayments of Principal in Year Five	2,823
Long-term Debt, Maturities, Repayments of Principal after Year Five	10,802
Unamortized Adjustments, Net	(116)
Debt and Capital Lease Obligations	15,746	$ 16,159
Total Cash Obligations	$ 15,862

Contractual Maturities [Abstract]

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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.

+ 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 210.9-03.13,16)
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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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
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Amount, after accumulated amortization, of debt discount.

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-Publisher FASB
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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the remainder of the fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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