Leases Supplemental Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Jan. 01, 2019	Dec. 31, 2018
Supplemental cash flow information related to leases [Abstract]
Operating Lease, Payments	$ 670
Finance Lease, Interest Payment on Liability	10
Finance Lease, Principal Payments	7
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	556
Right-of-Use Asset Obtained in Exchange for Finance Lease Liability	12
Supplemental balance sheet information related to leases [Abstract]
Operating lease right-of-use assets	20,992		$ 20,987	$ 0
Current portion of operating lease liabilities	1,803		1,803	0
Long-term operating lease liabilities	18,961		$ 18,832	$ 0
Operating Lease, Liability	20,764
Finance Lease, Right-of-Use Asset	509
Finance Lease, Liability, Current	25
Finance Lease, Liability, Noncurrent	535
Finance Lease, Liability	$ 560
Operating Lease, Weighted Average Remaining Lease Term	14 years 2 months 12 days
Finance Lease, Weighted Average Remaining Lease Term	20 years 3 months 18 days
Operating Lease, Weighted Average Discount Rate, Percent	4.70%
Finance Lease, Weighted Average Discount Rate, Percent	7.50%
Sale Leaseback Transaction, Net Proceeds, Investing Activities	$ 5
Store Rationalization Charges	$ 135	$ 0
Retail stores, mail order facilities and certain distribution centers and corp offices | Minimum [Member]
Lessee, Operating Lease, Term of Contract	15 years
Retail stores, mail order facilities and certain distribution centers and corp offices | Maximum [Member]
Lessee, Operating Lease, Term of Contract	25 years
Equipment and other assets | Minimum [Member]
Lessee, Operating Lease, Term of Contract	3 years
Equipment and other assets | Maximum [Member]
Lessee, Operating Lease, Term of Contract	10 years