Consolidating Financial Information - Condensed Consolidating Statement of Cash Flows (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Cash Flows from Operating Activities:
Total Cash Flows from Operating Activities	$ (364)	$ (389)
Cash Flows from Investing Activities:
Capital Expenditures	(221)	(248)
Short Term Securities Acquired	(31)	(8)
Short Term Securities Redeemed	31	8
Capital Contributions and Loans Incurred	0	0
Capital Redemptions and Loans Paid	0	0
Notes Receivable	(7)	0
Other Transactions	(16)	0
Total Cash Flows from Investing Activities	(244)	(248)
Cash Flows from Financing Activities:
Short Term Debt and Overdrafts Incurred	571	584
Short Term Debt and Overdrafts Paid	(485)	(518)
Long Term Debt Incurred	1,850	1,652
Long Term Debt Paid	(1,223)	(1,226)
Common Stock Issued	0	1
Common Stock Repurchased	0	(25)
Common Stock Dividends Paid	(37)	(34)
Capital Contributions and Loans Incurred	0	0
Capital Redemptions and Loans Paid	0	0
Intercompany Dividends Paid	0
Transactions with Minority Interests in Subsidiaries	0	(22)
Debt Related Costs and Other Transactions	(31)	(13)
Total Cash Flows from Financing Activities	645	399
Effect of Exchange Rate Changes on Cash, Cash Equivalents and Restricted Cash	0	16
Net Change in Cash, Cash Equivalents and Restricted Cash	37	(222)
Cash, Cash Equivalents and Restricted Cash at Beginning of the Period	873	1,110
Cash, Cash Equivalents and Restricted Cash at End of the Period	910	888
Reportable Legal Entities | Parent Company
Cash Flows from Operating Activities:
Total Cash Flows from Operating Activities	(75)	266
Cash Flows from Investing Activities:
Capital Expenditures	(90)	(101)
Short Term Securities Acquired	0	0
Short Term Securities Redeemed	0	0
Capital Contributions and Loans Incurred	(196)	(91)
Capital Redemptions and Loans Paid	104	38
Notes Receivable	(7)
Other Transactions	0
Total Cash Flows from Investing Activities	(189)	(154)
Cash Flows from Financing Activities:
Short Term Debt and Overdrafts Incurred	299	325
Short Term Debt and Overdrafts Paid	(269)	(325)
Long Term Debt Incurred	923	705
Long Term Debt Paid	(590)	(541)
Common Stock Issued		1
Common Stock Repurchased		(25)
Common Stock Dividends Paid	(37)	(34)
Capital Contributions and Loans Incurred	0	91
Capital Redemptions and Loans Paid	0	(360)
Intercompany Dividends Paid	0
Transactions with Minority Interests in Subsidiaries		0
Debt Related Costs and Other Transactions	(3)	7
Total Cash Flows from Financing Activities	323	(156)
Effect of Exchange Rate Changes on Cash, Cash Equivalents and Restricted Cash	0	0
Net Change in Cash, Cash Equivalents and Restricted Cash	59	(44)
Cash, Cash Equivalents and Restricted Cash at Beginning of the Period	168	201
Cash, Cash Equivalents and Restricted Cash at End of the Period	227	157
Reportable Legal Entities | Guarantor Subsidiaries
Cash Flows from Operating Activities:
Total Cash Flows from Operating Activities	(26)	0
Cash Flows from Investing Activities:
Capital Expenditures	(11)	(28)
Short Term Securities Acquired	0	0
Short Term Securities Redeemed	0	0
Capital Contributions and Loans Incurred	0	0
Capital Redemptions and Loans Paid	0	0
Notes Receivable	0
Other Transactions	0
Total Cash Flows from Investing Activities	(11)	(28)
Cash Flows from Financing Activities:
Short Term Debt and Overdrafts Incurred	0	0
Short Term Debt and Overdrafts Paid	0	0
Long Term Debt Incurred	0	15
Long Term Debt Paid	0	0
Common Stock Issued		0
Common Stock Repurchased		0
Common Stock Dividends Paid	0	0
Capital Contributions and Loans Incurred	34	8
Capital Redemptions and Loans Paid	0	0
Intercompany Dividends Paid	0
Transactions with Minority Interests in Subsidiaries		0
Debt Related Costs and Other Transactions	0	0
Total Cash Flows from Financing Activities	34	23
Effect of Exchange Rate Changes on Cash, Cash Equivalents and Restricted Cash	(1)	(1)
Net Change in Cash, Cash Equivalents and Restricted Cash	(4)	(6)
Cash, Cash Equivalents and Restricted Cash at Beginning of the Period	30	32
Cash, Cash Equivalents and Restricted Cash at End of the Period	26	26
Reportable Legal Entities | Non-Guarantor Subsidiaries
Cash Flows from Operating Activities:
Total Cash Flows from Operating Activities	(253)	(656)
Cash Flows from Investing Activities:
Capital Expenditures	(120)	(118)
Short Term Securities Acquired	(31)	(8)
Short Term Securities Redeemed	31	8
Capital Contributions and Loans Incurred	0	(91)
Capital Redemptions and Loans Paid	0	360
Notes Receivable	0
Other Transactions	(16)
Total Cash Flows from Investing Activities	(136)	151
Cash Flows from Financing Activities:
Short Term Debt and Overdrafts Incurred	272	259
Short Term Debt and Overdrafts Paid	(216)	(193)
Long Term Debt Incurred	927	932
Long Term Debt Paid	(633)	(685)
Common Stock Issued		0
Common Stock Repurchased		0
Common Stock Dividends Paid	0	0
Capital Contributions and Loans Incurred	162	83
Capital Redemptions and Loans Paid	(104)	(38)
Intercompany Dividends Paid	(10)
Transactions with Minority Interests in Subsidiaries		(22)
Debt Related Costs and Other Transactions	(28)	(20)
Total Cash Flows from Financing Activities	370	316
Effect of Exchange Rate Changes on Cash, Cash Equivalents and Restricted Cash	1	17
Net Change in Cash, Cash Equivalents and Restricted Cash	(18)	(172)
Cash, Cash Equivalents and Restricted Cash at Beginning of the Period	675	877
Cash, Cash Equivalents and Restricted Cash at End of the Period	657	705
Consolidating Entries and Eliminations
Cash Flows from Operating Activities:
Total Cash Flows from Operating Activities	(10)	1
Cash Flows from Investing Activities:
Capital Expenditures	0	(1)
Short Term Securities Acquired	0	0
Short Term Securities Redeemed	0	0
Capital Contributions and Loans Incurred	196	182
Capital Redemptions and Loans Paid	(104)	(398)
Notes Receivable	0
Other Transactions	0
Total Cash Flows from Investing Activities	92	(217)
Cash Flows from Financing Activities:
Short Term Debt and Overdrafts Incurred	0	0
Short Term Debt and Overdrafts Paid	0	0
Long Term Debt Incurred	0	0
Long Term Debt Paid	0	0
Common Stock Issued		0
Common Stock Repurchased		0
Common Stock Dividends Paid	0	0
Capital Contributions and Loans Incurred	(196)	(182)
Capital Redemptions and Loans Paid	104	398
Intercompany Dividends Paid	10
Transactions with Minority Interests in Subsidiaries		0
Debt Related Costs and Other Transactions	0	0
Total Cash Flows from Financing Activities	(82)	216
Effect of Exchange Rate Changes on Cash, Cash Equivalents and Restricted Cash	0	0
Net Change in Cash, Cash Equivalents and Restricted Cash	0	0
Cash, Cash Equivalents and Restricted Cash at Beginning of the Period	0	0
Cash, Cash Equivalents and Restricted Cash at End of the Period	$ 0	$ 0