Benefit Obligations (Schedule of Company Commitments to Fund Benefit Obligations) (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2012
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions to pension plans	$ 119	[1]
Expected employer contributions to pension plans in current fiscal year	144	[1]
Discretionary contributions	15
Expected discretionary contributions	15
Nonqualified Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions to pension plans	17
Expected employer contributions to pension plans in current fiscal year	21
Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions to pension plans	18
Expected employer contributions to pension plans in current fiscal year	$ 25

[1] Includes $15 million of discretionary contributions as of September 30, 2012 and $15 million of expected discretionary contributions.