Organization and Basis of Presentation (Consolidated Variable Interest Entities) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Assets [Abstract]
Cash and cash equivalents	$ 92	$ 37	$ 48	$ 52
Restricted cash	21	23
Accounts receivable	1,522	1,276
Property, plant, and equipment, net	19,730	18,034
Goodwill	2,286	2,018	2,018
Total Assets	32,041	28,662	$ 27,827
Liabilities [Abstract]
Current portion long-term debt, including capital leases	14	473
Mortgage bonds, notes, and other	10,506	8,280
Variable interest entity, primary beneficiary, restricted
Assets [Abstract]
Cash and cash equivalents	63	14
Restricted cash	7	8
Accounts receivable	42	18
Inventories	115	82
Property, plant, and equipment, net	474	66
Goodwill	17	0
Intangible assets	586	0
Other current and long-term assets	2	4
Total Assets	1,306	192
Liabilities [Abstract]
Accounts payable and accrued current liabilities	51	13
Current portion long-term debt, including capital leases	5	8
Mortgage bonds, notes, and other	5	10
Other current and long-term liabilities	17	6
Total liabilities	78	$ 37
Variable interest entity, primary beneficiary, SGG
Assets [Abstract]
Cash and cash equivalents	36
Restricted cash	0
Accounts receivable	8
Inventories	3
Property, plant, and equipment, net	398
Goodwill	17
Intangible assets	586
Other current and long-term assets	1
Total Assets	1,049
Liabilities [Abstract]
Accounts payable and accrued current liabilities	19
Current portion long-term debt, including capital leases	0
Mortgage bonds, notes, and other	0
Other current and long-term liabilities	2
Total liabilities	$ 21
VIE percentage	100.00%
VIE ownership percentage	55.00%
Variable interest entity, primary beneficiary other, restricted
Assets [Abstract]
Cash and cash equivalents	$ 27
Restricted cash	7
Accounts receivable	34
Inventories	112
Property, plant, and equipment, net	76
Goodwill	0
Intangible assets	0
Other current and long-term assets	1
Total Assets	257
Liabilities [Abstract]
Accounts payable and accrued current liabilities	32
Current portion long-term debt, including capital leases	5
Mortgage bonds, notes, and other	5
Other current and long-term liabilities	15
Total liabilities	$ 57