Consolidated Statements of Cash Flows - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Cash flows from operating activities:
Net income	$ 1,040	$ 1,040
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation and amortization	1,274	1,197
Allowance for equity funds	(130)	(61)
Equity income, net of distributions	(44)	(20)
Increase (Decrease) in Regulatory Assets and Liabilities	(1)	243
Deferred income taxes and amortization of investment tax credits	291	390
Other, net	(72)	13
Changes in other operating assets and liabilities, net of effects from acquisitions:
Increase (Decrease) in Accounts Receivable and Other Operating Assets	(252)	(418)
Derivative collateral, net	23	5
Pension and other postretirement benefit plans	(9)	(7)
Accrued property, income and other taxes	557	1,199
Accounts payable and other liabilities	94	(48)
Net cash flows from operating activities	2,771	3,533
Cash flows from investing activities:
Capital expenditures	(2,103)	(2,624)
Acquisitions, net of cash acquired	(66)	(59)
Decrease in restricted cash and investments	9	20
Purchases of available-for-sale securities	(55)	(102)
Proceeds from sales of available-for-sale securities	88	95
Equity method investments	(282)	(18)
Other, net	(46)	43
Net cash flows from investing activities	(2,455)	(2,645)
Cash flows from financing activities:
Repayments of Subordinated Debt	1,000	600
Common stock purchases	0	(36)
Proceeds from subsidiary debt	1,461	1,238
Repayments of subsidiary debt	(1,529)	(527)
Net proceeds from (repayments of) short-term debt	465	(405)
Other, net	(39)	(43)
Net cash flows from financing activities	(642)	(373)
Effect of exchange rate changes	(4)	0
Net change in cash and cash equivalents	(330)	515
Cash and cash equivalents at beginning of period	1,108	617
Cash and cash equivalents at end of period	$ 778	$ 1,132