Schedule I - Condensed Financial Information Of Parent (Statement of Cash Flows) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities	$ 1,693	$ 1,690	$ 1,878
Cash Flows From Investing Activities:
Other	2	2	15
Net cash used in investing activities	(1,723)	(1,310)	(1,048)
Cash flows from financing activities:
Dividends on common stock	(388)	(382)	(375)
Short-term debt and credit facility borrowings, net	368	(148)	(481)
Issuances:
Long-term debt	278	882
Common stock			65
Net cash provided by (used in) financing activities	(149)	(426)	(1,120)
Net change in cash and cash equivalents	(179)	(46)	(290)
Cash and cash equivalents at beginning of year	184	248
Cash and cash equivalents at end of year	30	184	248
Noncash financing activity – dividends on common stock		7
Parent Company
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities	453	532	804
Cash Flows From Investing Activities:
Money pool advances, net	(371)	24	(276)
Intercompany notes receivable, net	(23)	(20)	358
Investments in subsidiaries	(50)	(2)	(94)
Return of investments	1	21	3
Other	(2)	(5)	(5)
Net cash used in investing activities	(445)	18	(14)
Cash flows from financing activities:
Dividends on common stock	(388)	(382)	(375)
Short-term debt and credit facility borrowings, net	368	(148)	(481)
Issuances:
Common stock			65
Net cash provided by (used in) financing activities	(20)	(530)	(791)
Net change in cash and cash equivalents	(12)	20	(1)
Cash and cash equivalents at beginning of year	23	3	4
Cash and cash equivalents at end of year	11	23	3
Cash dividends received from consolidated subsidiaries	570	610	730
Noncash investing activity - divestiture	494
Noncash financing activity – dividends on common stock		$ (7)