Benefit Obligations (Schedule of Company Commitments to Fund Benefit Obligations) (Details) $ in Millions	6 Months Ended
	Jun. 30, 2016 USD ($)
Multiemployer Plans, Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Total contributions year-to-date	$ 4	[1]
Total expected contributions in current fiscal year	8	[1]
Cash Contributions to Defined Benefit Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Total contributions year-to-date	13
Total expected contributions in current fiscal year	23
Other Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total contributions year-to-date	11
Total expected contributions in current fiscal year	22
Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Total contributions year-to-date	2
Total expected contributions in current fiscal year	$ 4

[1] The Company makes contributions based on specified percentages of employee contributions.