Schedule I - Condensed Financial Information - Balance Sheet (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current Assets
Cash and temporary cash investments	$ 981	$ 895
Taxes receivable	20	49
Prepayments	260	187
Other current assets	200	122
TOTAL CURRENT ASSETS	4,272	3,864
Investments in subsidiaries and others	2,065	1,766
Goodwill	446	440
Other noncurrent assets	7,853	6,541
TOTAL ASSETS	58,079	53,920	$ 48,111
Current Liabilities
Long-term debt due within one year	1,446	650
Term Loan	0	825
Notes payable	1,692	1,741
Accounts payable	1,164	1,187
Accrued taxes	76	61
Other current liabilities	371	363
TOTAL CURRENT LIABILITIES	6,287	6,207
Long-term debt	18,527	17,495
Shareholders’ Equity
Equity	18,022	16,726
TOTAL LIABILITIES AND EQUITY	58,079	53,920
Parent Company
Current Assets
Cash and temporary cash investments	2	9
Taxes receivable	18	43
Term loan receivable from affiliated companies	0	825
Accounts receivable from affiliated companies	870	536
Prepayments	32	33
Other current assets	12	12
TOTAL CURRENT ASSETS	934	1,458
Investments in subsidiaries and others	18,009	16,707
Goodwill	406	406
Deferred income tax	14	69
Long-term debt receivable from affiliated companies	1,275	900
Other noncurrent assets	0	2
TOTAL ASSETS	20,638	19,542
Current Liabilities
Long-term debt due within one year	3	3
Term Loan	0	825
Notes payable	537	495
Accounts payable	0	9
Accounts payable to affiliated companies	595	274
Accrued taxes	2	2
Other current liabilities	10	13
TOTAL CURRENT LIABILITIES	1,147	1,621
Deferred income tax	0	0
Total Liabilities	1,147	1,621
Long-term debt	1,469	1,195
Shareholders’ Equity
Common stock, including additional paid-in capital	8,089	7,151
Retained earnings	9,933	9,575
Equity	18,022	16,726
TOTAL LIABILITIES AND EQUITY	$ 20,638	$ 19,542