Consolidating Financial Information - Condensed Consolidating Statement of Cash Flows (Details) - USD ($) $ in Millions	12 Months Ended			75 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2019
Cash Flows from Operating Activities:
Total Cash Flows from Operating Activities	$ 1,207	$ 916	$ 1,158
Cash Flows from Investing Activities:
Capital Expenditures	(770)	(811)	(881)
Asset Dispositions	12	2	12
Short Term Securities Acquired	(113)	(68)	(83)
Short Term Securities Redeemed	106	68	83
Capital Contributions and Loans Incurred	0	0	0
Capital Redemptions and Loans Paid	0	0	0
Notes Receivable	(7)	(55)	0
Other Transactions	(28)	(3)	(10)
Total Cash Flows from Investing Activities	(800)	(867)	(879)
Cash Flows from Financing Activities:
Short Term Debt and Overdrafts Incurred	1,880	1,944	1,054
Short Term Debt and Overdrafts Paid	(1,933)	(1,795)	(1,046)
Long Term Debt Incurred	5,942	6,455	6,463
Long Term Debt Paid	(6,008)	(6,469)	(6,342)
Common Stock Issued	1	4	14
Common Stock Repurchased	0	(220)	(400)	$ (1,534)
Common Stock Dividends Paid	(148)	(138)	(110)
Capital Contributions and Loans Incurred	0	0	0
Capital Redemptions and Loans Paid	0	0	0
Intercompany Dividends Paid	0	0	0
Transactions with Minority Interests in Subsidiaries	(26)	(31)	(7)
Debt Related Costs and Other Transactions	(15)	7	(41)
Total Cash Flows from Financing Activities	(307)	(243)	(415)
Effect of Exchange Rate Changes on Cash, Cash Equivalents and Restricted Cash	1	(43)	57
Net Change in Cash, Cash Equivalents and Restricted Cash	101	(237)	(79)
Cash, Cash Equivalents and Restricted Cash at Beginning of the Year	873	1,110	1,189
Cash, Cash Equivalents and Restricted Cash at End of the Year	974	873	1,110	974
Reportable Legal Entities | Parent Company
Cash Flows from Operating Activities:
Total Cash Flows from Operating Activities	3,541	1,771	1,192
Cash Flows from Investing Activities:
Capital Expenditures	(288)	(307)	(305)
Asset Dispositions	0	0	1
Short Term Securities Acquired	0	0	0
Short Term Securities Redeemed	0	0	0
Capital Contributions and Loans Incurred	(3,286)	(1,205)	(79)
Capital Redemptions and Loans Paid	269	282	76
Notes Receivable	(7)	(55)	0
Other Transactions	(18)	1	(3)
Total Cash Flows from Investing Activities	(3,330)	(1,284)	(310)
Cash Flows from Financing Activities:
Short Term Debt and Overdrafts Incurred	398	965	420
Short Term Debt and Overdrafts Paid	(423)	(940)	(420)
Long Term Debt Incurred	2,981	3,200	3,062
Long Term Debt Paid	(2,983)	(3,260)	(3,151)
Common Stock Issued	1	4	14
Common Stock Repurchased	0	(220)	(400)
Common Stock Dividends Paid	(148)	(138)	(110)
Capital Contributions and Loans Incurred	0	283	292
Capital Redemptions and Loans Paid	0	(430)	(563)
Intercompany Dividends Paid	0	0	0
Transactions with Minority Interests in Subsidiaries	0	0	0
Debt Related Costs and Other Transactions	(1)	16	(35)
Total Cash Flows from Financing Activities	(175)	(520)	(891)
Effect of Exchange Rate Changes on Cash, Cash Equivalents and Restricted Cash	0	0	0
Net Change in Cash, Cash Equivalents and Restricted Cash	36	(33)	(9)
Cash, Cash Equivalents and Restricted Cash at Beginning of the Year	168	201	210
Cash, Cash Equivalents and Restricted Cash at End of the Year	204	168	201	204
Reportable Legal Entities | Guarantor Subsidiaries
Cash Flows from Operating Activities:
Total Cash Flows from Operating Activities	(273)	32	67
Cash Flows from Investing Activities:
Capital Expenditures	(40)	(61)	(136)
Asset Dispositions	0	2	1
Short Term Securities Acquired	0	0	0
Short Term Securities Redeemed	0	0	0
Capital Contributions and Loans Incurred	0	0	0
Capital Redemptions and Loans Paid	0	88	0
Notes Receivable	0	0	0
Other Transactions	0	0	0
Total Cash Flows from Investing Activities	(40)	29	(135)
Cash Flows from Financing Activities:
Short Term Debt and Overdrafts Incurred	0	0	0
Short Term Debt and Overdrafts Paid	0	0	0
Long Term Debt Incurred	0	15	204
Long Term Debt Paid	0	0	(52)
Common Stock Issued	0	0	0
Common Stock Repurchased	0	0	0
Common Stock Dividends Paid	0	0	0
Capital Contributions and Loans Incurred	388	67	66
Capital Redemptions and Loans Paid	(57)	(77)	(48)
Intercompany Dividends Paid	(3)	(65)	(128)
Transactions with Minority Interests in Subsidiaries	0	0	0
Debt Related Costs and Other Transactions	0	0	0
Total Cash Flows from Financing Activities	328	(60)	42
Effect of Exchange Rate Changes on Cash, Cash Equivalents and Restricted Cash	1	(3)	3
Net Change in Cash, Cash Equivalents and Restricted Cash	16	(2)	(23)
Cash, Cash Equivalents and Restricted Cash at Beginning of the Year	30	32	55
Cash, Cash Equivalents and Restricted Cash at End of the Year	46	30	32	46
Reportable Legal Entities | Non-Guarantor Subsidiaries
Cash Flows from Operating Activities:
Total Cash Flows from Operating Activities	82	(279)	577
Cash Flows from Investing Activities:
Capital Expenditures	(442)	(443)	(442)
Asset Dispositions	12	0	10
Short Term Securities Acquired	(113)	(68)	(83)
Short Term Securities Redeemed	106	68	83
Capital Contributions and Loans Incurred	(320)	(283)	(292)
Capital Redemptions and Loans Paid	0	430	563
Notes Receivable	0	0	0
Other Transactions	(2,110)	(4)	(7)
Total Cash Flows from Investing Activities	(2,867)	(300)	(168)
Cash Flows from Financing Activities:
Short Term Debt and Overdrafts Incurred	1,482	979	634
Short Term Debt and Overdrafts Paid	(1,510)	(855)	(626)
Long Term Debt Incurred	2,961	3,240	3,197
Long Term Debt Paid	(3,025)	(3,209)	(3,139)
Common Stock Issued	0	0	0
Common Stock Repurchased	0	0	0
Common Stock Dividends Paid	0	0	0
Capital Contributions and Loans Incurred	3,218	1,138	13
Capital Redemptions and Loans Paid	(212)	(293)	(28)
Intercompany Dividends Paid	(40)	(543)	(548)
Transactions with Minority Interests in Subsidiaries	(26)	(31)	(7)
Debt Related Costs and Other Transactions	(14)	(9)	(6)
Total Cash Flows from Financing Activities	2,834	417	(510)
Effect of Exchange Rate Changes on Cash, Cash Equivalents and Restricted Cash	0	(40)	54
Net Change in Cash, Cash Equivalents and Restricted Cash	49	(202)	(47)
Cash, Cash Equivalents and Restricted Cash at Beginning of the Year	675	877	924
Cash, Cash Equivalents and Restricted Cash at End of the Year	724	675	877	724
Consolidating Entries and Eliminations
Cash Flows from Operating Activities:
Total Cash Flows from Operating Activities	(2,143)	(608)	(678)
Cash Flows from Investing Activities:
Capital Expenditures	0	0	2
Asset Dispositions	0	0	0
Short Term Securities Acquired	0	0	0
Short Term Securities Redeemed	0	0	0
Capital Contributions and Loans Incurred	3,606	1,488	371
Capital Redemptions and Loans Paid	(269)	(800)	(639)
Notes Receivable	0	0	0
Other Transactions	2,100	0	0
Total Cash Flows from Investing Activities	5,437	688	(266)
Cash Flows from Financing Activities:
Short Term Debt and Overdrafts Incurred	0	0	0
Short Term Debt and Overdrafts Paid	0	0	0
Long Term Debt Incurred	0	0	0
Long Term Debt Paid	0	0	0
Common Stock Issued	0	0	0
Common Stock Repurchased	0	0	0
Common Stock Dividends Paid	0	0	0
Capital Contributions and Loans Incurred	(3,606)	(1,488)	(371)
Capital Redemptions and Loans Paid	269	800	639
Intercompany Dividends Paid	43	608	676
Transactions with Minority Interests in Subsidiaries	0	0	0
Debt Related Costs and Other Transactions	0	0	0
Total Cash Flows from Financing Activities	(3,294)	(80)	944
Effect of Exchange Rate Changes on Cash, Cash Equivalents and Restricted Cash	0	0	0
Net Change in Cash, Cash Equivalents and Restricted Cash	0	0	0
Cash, Cash Equivalents and Restricted Cash at Beginning of the Year	0	0	0
Cash, Cash Equivalents and Restricted Cash at End of the Year	$ 0	$ 0	$ 0	$ 0