Benefit Obligations (Schedule of Company Commitments to Fund Benefit Obligations) (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2012
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions to pension plans	$ 88
Expected employer contributions to pension plans in current fiscal year	160
Nonqualified Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions to pension plans	7
Expected employer contributions to pension plans in current fiscal year	15
Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions to pension plans	13
Expected employer contributions to pension plans in current fiscal year	$ 25