Common Stock And Share-Based Compensation (Performance Shares) (Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance period for vesting of performance shares, years	3 years
Employee service share based compensation nonvested performance shares total compensation cost not yet recognized	$ 34
Weighted-average period (years)	1 year 2 months 0 days
Performance Shares, Equity Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Nonvested at January 1, Number of Performance Shares	1,791,320
Granted, Number of Performance Shares	843,185
Vested, Number of Performance Shares	(275,247)
Forfeited, Number of Performance Shares	(665,319)	[1]
Nonvested at December 31, Number of Performance Shares	1,693,939		1,791,320
Nonvested at January 1, Weighted Average Exercise Price	$ 37.85
Granted, Weighted Average Exercise Price	51.81		33.45	41.93
Vested, Weighted Average Exercise Price	41.94
Forfeited, Weighted Average Exercise Price	42.34
Nonvested at December 31, Weighted Average Exercise Price	$ 42.37		$ 37.85

[1] Includes performance shares that expired with zero value as performance targets were not met.