Consolidating Financial Information - Consolidating Statement of Cash Flows (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Cash Flows from Operating Activities:
Total Cash Flows from Operating Activities	$ (120)	$ 274
Cash Flows from Investing Activities:
Capital Expenditures	(466)	(448)
Asset Dispositions	1	8
Decrease (Increase) in Restricted Cash	11	(6)
Short Term Securities Acquired	(34)	(49)
Short Term Securities Redeemed	23	21
Capital Contributions and Loans Incurred	0	0
Other Transactions	0	5
Capital Redemptions and Loans Paid	0
Total Cash Flows from Investing Activities	(465)	(469)
Cash Flows from Financing Activities:
Short Term Debt and Overdrafts Incurred	124	49
Short Term Debt and Overdrafts Paid	(36)	(43)
Long Term Debt Incurred	3,283	1,116
Long Term Debt Paid	(2,931)	(1,312)
Common Stock Issued	3	18
Common Stock Repurchased	(150)	(52)
Common Stock Dividends Paid	(38)	(32)
Capital Contributions and Loans Incurred	0	0
Capital Redemptions and Loans Paid	0
Intercompany Dividends Paid	0	0
Transactions with Minority Interests in Subsidiaries	(7)	(1)
Debt Related Costs and Other Transactions	(23)	(10)
Total Cash Flows from Financing Activities	225	(267)
Effect of Exchange Rate Changes on Cash and Cash Equivalents	22	(61)
Net Change in Cash and Cash Equivalents	(338)	(523)
Cash and Cash Equivalents at Beginning of the Period	1,476	2,161
Cash and Cash Equivalents at End of the Period	1,138	1,638
Parent Company
Cash Flows from Operating Activities:
Total Cash Flows from Operating Activities	(243)	231
Cash Flows from Investing Activities:
Capital Expenditures	(185)	(184)
Asset Dispositions	0	0
Decrease (Increase) in Restricted Cash	0	0
Short Term Securities Acquired	0	0
Short Term Securities Redeemed	0	0
Capital Contributions and Loans Incurred	(93)	(12)
Other Transactions		0
Capital Redemptions and Loans Paid	25
Total Cash Flows from Investing Activities	(253)	(196)
Cash Flows from Financing Activities:
Short Term Debt and Overdrafts Incurred	0	43
Short Term Debt and Overdrafts Paid	(4)	(5)
Long Term Debt Incurred	2,051	455
Long Term Debt Paid	(1,523)	(658)
Common Stock Issued	3	18
Common Stock Repurchased	(150)	(52)
Common Stock Dividends Paid	(38)	(32)
Capital Contributions and Loans Incurred	243	0
Capital Redemptions and Loans Paid	(143)
Intercompany Dividends Paid	0	0
Transactions with Minority Interests in Subsidiaries	0	0
Debt Related Costs and Other Transactions	(22)	(1)
Total Cash Flows from Financing Activities	417	(232)
Effect of Exchange Rate Changes on Cash and Cash Equivalents	0	0
Net Change in Cash and Cash Equivalents	(79)	(197)
Cash and Cash Equivalents at Beginning of the Period	354	674
Cash and Cash Equivalents at End of the Period	275	477
Guarantor Subsidiaries
Cash Flows from Operating Activities:
Total Cash Flows from Operating Activities	(11)	(14)
Cash Flows from Investing Activities:
Capital Expenditures	(44)	(16)
Asset Dispositions	0	0
Decrease (Increase) in Restricted Cash	0	0
Short Term Securities Acquired	0	0
Short Term Securities Redeemed	0	0
Capital Contributions and Loans Incurred	0	0
Other Transactions		0
Capital Redemptions and Loans Paid	0
Total Cash Flows from Investing Activities	(44)	(16)
Cash Flows from Financing Activities:
Short Term Debt and Overdrafts Incurred	4	5
Short Term Debt and Overdrafts Paid	0	0
Long Term Debt Incurred	0	0
Long Term Debt Paid	0	0
Common Stock Issued	0	0
Common Stock Repurchased	0	0
Common Stock Dividends Paid	0	0
Capital Contributions and Loans Incurred	59	12
Capital Redemptions and Loans Paid	(25)
Intercompany Dividends Paid	0	0
Transactions with Minority Interests in Subsidiaries	0	0
Debt Related Costs and Other Transactions	0	0
Total Cash Flows from Financing Activities	38	17
Effect of Exchange Rate Changes on Cash and Cash Equivalents	2	(6)
Net Change in Cash and Cash Equivalents	(15)	(19)
Cash and Cash Equivalents at Beginning of the Period	70	89
Cash and Cash Equivalents at End of the Period	55	70
Non-Guarantor Subsidiaries
Cash Flows from Operating Activities:
Total Cash Flows from Operating Activities	151	75
Cash Flows from Investing Activities:
Capital Expenditures	(239)	(251)
Asset Dispositions	1	8
Decrease (Increase) in Restricted Cash	11	(6)
Short Term Securities Acquired	(34)	(49)
Short Term Securities Redeemed	23	21
Capital Contributions and Loans Incurred	(243)	0
Other Transactions		5
Capital Redemptions and Loans Paid	143
Total Cash Flows from Investing Activities	(338)	(272)
Cash Flows from Financing Activities:
Short Term Debt and Overdrafts Incurred	124	49
Short Term Debt and Overdrafts Paid	(36)	(86)
Long Term Debt Incurred	1,232	661
Long Term Debt Paid	(1,408)	(654)
Common Stock Issued	0	0
Common Stock Repurchased	0	0
Common Stock Dividends Paid	0	0
Capital Contributions and Loans Incurred	34	0
Capital Redemptions and Loans Paid	0
Intercompany Dividends Paid	(15)	(15)
Transactions with Minority Interests in Subsidiaries	(7)	(1)
Debt Related Costs and Other Transactions	(1)	(9)
Total Cash Flows from Financing Activities	(77)	(55)
Effect of Exchange Rate Changes on Cash and Cash Equivalents	20	(55)
Net Change in Cash and Cash Equivalents	(244)	(307)
Cash and Cash Equivalents at Beginning of the Period	1,052	1,398
Cash and Cash Equivalents at End of the Period	808	1,091
Consolidating Entries and Eliminations
Cash Flows from Operating Activities:
Total Cash Flows from Operating Activities	(17)	(18)
Cash Flows from Investing Activities:
Capital Expenditures	2	3
Asset Dispositions	0	0
Decrease (Increase) in Restricted Cash	0	0
Short Term Securities Acquired	0	0
Short Term Securities Redeemed	0	0
Capital Contributions and Loans Incurred	336	12
Other Transactions		0
Capital Redemptions and Loans Paid	(168)
Total Cash Flows from Investing Activities	170	15
Cash Flows from Financing Activities:
Short Term Debt and Overdrafts Incurred	(4)	(48)
Short Term Debt and Overdrafts Paid	4	48
Long Term Debt Incurred	0	0
Long Term Debt Paid	0	0
Common Stock Issued	0	0
Common Stock Repurchased	0	0
Common Stock Dividends Paid	0	0
Capital Contributions and Loans Incurred	(336)	(12)
Capital Redemptions and Loans Paid	168
Intercompany Dividends Paid	15	15
Transactions with Minority Interests in Subsidiaries	0	0
Debt Related Costs and Other Transactions	0	0
Total Cash Flows from Financing Activities	(153)	3
Effect of Exchange Rate Changes on Cash and Cash Equivalents	0	0
Net Change in Cash and Cash Equivalents	0	0
Cash and Cash Equivalents at Beginning of the Period	0	0
Cash and Cash Equivalents at End of the Period	$ 0	$ 0