Stock-Based Compensation (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Summary of components of stock-based compensation expense
Stock-based compensation expense	$ 11	$ 13	$ 29	$ 29
Tax benefit	4	5	11	11
Stock-based compensation cost capitalized in property, plant and equipment	1	1	2	2
Summary of Company's stock option activity
Number of Options, Options outstanding, beginning balance			4,827,457
Number of Options, Granted			0
Number of Options, Exercised			(1,450,974)
Number of Options, Forfeited or expired			(21,288)
Number of Options outstanding, ending balance	3,355,195		3,355,195
Number of options exercisable	2,688,709		2,688,709
Weighted Average Exercise Price, Options outstanding, beginning balance			$ 41.09
Weighted Average Exercise Price, Granted			$ 0
Weighted Average Exercise Price, Exercised			$ 40.55
Weighted Average Exercise Price, Forfeited or expired			$ 43.47
Weighted Average Exercise Price, Options outstanding, Ending balance	$ 41.30		$ 41.30
Weighted average exercise price options exercisable	$ 42.23		$ 42.23
Aggregate Intrinsic Value, ending balance	29.72		29.72
Aggregate intrinsic value of options exercisable	21.33		21.33
Summary of stock awards activity
Balance at January 1, 2010			757,414
Balance at January 1, 2010, Weighted Average Grant Date Fair Value			$ 37.32
Grants			380,840
Grants, Weighted Average Grant Date Fair Value			$ 47.98
Forfeitures			(18,692)
Forfeitures, Weighted Average Grant Date Fair Value			$ 38.24
Vested and issued			(263,237)
Vested and issued, Weighted Average Grant Date Fair Value			$ 39.60
Balance at June 30, 2011	856,325		856,325
Balance at Balance at June 30, 2011, Weighted Average Grant Date Fair Value	$ 41.42		$ 41.42
Summary of performance share activity
Performance Shares, Opening Balance			1,527,253
Performance Shares, Grants			597,372
Performance Shares, Forfeitures			(12,096)
Performance Shares, Payouts			(467,688)
Performance Shares, Closing Balance	1,644,841		1,644,841
Stock Based Compensation (Textuals) [Abstract]
Weighted average remaining contractual life for the exercisable shares	4.59		4.59
Stock Options Non-vested	666,486		666,486
Stock Options vested			687,061
Intrinsic value of options exercised			14.0
Option expense recognized			1.0	2.0
Unrecognized compensation cost related to non-vested stock incentive plan arrangements	$ 68		$ 68
Weighted-average period for costs recognized			1.53