Long Term Debt (Long-Term Debt) (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Long-term debt, beginning balance	$ 17,400
Payments and Retirements	(2,270)
New Borrowings	2,025
Long-term debt, ending balance	17,155
Long-term debt	17,400	$ 17,155	$ 17,400
Less: Debt Issuance Cost		(187)	(178)
Less: Debt Premium (Discount)		(49)	(50)
Less: Current Portion		(393)	(814)
Total Long term debt		$ 16,526	16,358
Interest rate		8.90%
Secured Debt [Member]
Debt Instrument [Line Items]
Long-term debt, beginning balance	5,246
Long-term debt, ending balance	5,350
Long-term debt	5,246	$ 5,350	5,246
Secured Debt [Member] \| Parent Company [Member]
Debt Instrument [Line Items]
Long-term debt, beginning balance	5,246
Payments and Retirements	(1,921)
New Borrowings	2,025
Long-term debt, ending balance	5,350
Long-term debt	5,246	$ 5,350	5,246
Interest rate		7.68%
Secured Debt [Member] \| Subsidiaries [Member]
Debt Instrument [Line Items]
Long-term debt, beginning balance	107
Payments and Retirements	(1)
Long-term debt, ending balance	106
Long-term debt	107	$ 106	107
Interest rate		8.36%
Unsecured Debt [Member]
Debt Instrument [Line Items]
Long-term debt, beginning balance	11,297
Long-term debt, ending balance	10,949
Long-term debt	11,297	$ 10,949	11,297
Unsecured Debt [Member] \| Parent Company [Member]
Debt Instrument [Line Items]
Long-term debt, beginning balance	11,297
Payments and Retirements	(348)
Long-term debt, ending balance	10,949
Long-term debt	11,297	$ 10,949	11,297
Interest rate		9.64%
Unsecured Debt [Member] \| Subsidiaries [Member]
Debt Instrument [Line Items]
Long-term debt, beginning balance	750
Long-term debt, ending balance	750
Long-term debt	$ 750	$ 750	$ 750
Interest rate		6.90%

Weighted average interest rate of long-term debt including debt issuance costs, premiums and or discounts.

No definition available.

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- Definition

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/disclosureRef
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- Definition

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.

+ References

No definition available.

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- Definition

Amount, after accumulated amortization, of debt discount (premium).

+ References

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- Definition

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

+ References

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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.

+ 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.

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- Definition

The cash inflow during the period from additional borrowings in aggregate debt. Includes proceeds from short-term and long-term debt.

+ References

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The cash outflow during the period from the repayment of aggregate short-term and long-term debt. Excludes payment of capital lease obligations.

+ References

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