Common Shareholders' Equity (Earnings Per Share) (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013
Reconciliation of basic and diluted earnings per share of common stock [Abstract]
Income (loss) from continuing operations	$ 430		$ 41	[1],[2]
Denominator:
Weighted-average number of common shares outstanding - basic (in shares)	433.5		421.0
Performance share awards, options, equity units and restricted stock (in shares)	4.7	[3]	2.7	[3]
Weighted-average number of common shares outstanding - assuming dilution (in shares)	438.2		423.7
Earnings per share of common stock from continuing operations:
Basic	$ 0.99		$ 0.10
Assuming dilution	$ 0.98		$ 0.10
Antidilutive securities (in shares)	0.1		0.4

[1] (c)Prior year amounts were restated to conform to current year's presentation. See Note 3 - Nonrecurring Fair Value Measurements.

[2] Certain amounts were restated to conform to current year's presentation. See Note 3 - Nonrecurring Fair Value Measurements

[3] Calculated using the treasury stock method. Performance share awards are included in diluted weighted-average number of common shares outstanding based upon what would be issued if the end of the reporting period was the end of the term of the award.